diff --git a/cmd/test/main.go b/cmd/test/main.go
index 40fdd01..1bb729c 100644
--- a/cmd/test/main.go
+++ b/cmd/test/main.go
@@ -150,13 +150,29 @@ func mutateMessage(fn func(string) string) tx.ActionFunc {
 	}
 }
 
+var gBeh = tx.NewGroupBehaviour().
+	InitFunc(func(a *tx.GA) {
+	}).
+	WithCommands(
+		tx.NewGroupCommand("hello").ActionFunc(func(a *tx.GA) {
+			a.Send("Hello, World!")
+		}),
+		tx.NewGroupCommand("mycounter").ActionFunc(func(a *tx.GA) {
+			d := a.GetSessionValue().(*UserData)
+			a.Sendf("Your counter value is %d", d.Counter)
+		}),
+	)
+
 func main() {
 	token := os.Getenv("BOT_TOKEN")
 
-	bot, err := tx.NewBot(token, beh, nil)
+	bot, err := tx.NewBot(token)
 	if err != nil {
 		log.Panic(err)
 	}
+	bot = bot.
+		WithBehaviour(beh).
+		WithGroupBehaviour(gBeh)
 
 	bot.Debug = true
 
diff --git a/src/tx/action.go b/src/tx/action.go
index 8e93d84..96756b8 100644
--- a/src/tx/action.go
+++ b/src/tx/action.go
@@ -1,10 +1,41 @@
 package tx
 
-import (
-	apix "github.com/go-telegram-bot-api/telegram-bot-api/v5"
-)
+//apix "github.com/go-telegram-bot-api/telegram-bot-api/v5"
 
-type Update = apix.Update
+type Action interface {
+	Act(*Arg)
+}
+
+type GroupAction interface {
+	Act(*GroupArg)
+}
+
+// Customized actions for the bot.
+
+type ActionFunc func(*Arg)
+
+func (af ActionFunc) Act(a *Arg) {
+	af(a)
+}
+
+type GroupActionFunc func(*GroupArg)
+
+func (af GroupActionFunc) Act(a *GroupArg) {
+	af(a)
+}
+
+// The type implements changing screen to the underlying ScreenId
+type ScreenChange ScreenId
+
+func (sc ScreenChange) Act(c *Arg) {
+	if !c.B.behaviour.ScreenExist(ScreenId(sc)) {
+		panic(ScreenNotExistErr)
+	}
+	err := c.ChangeScreen(ScreenId(sc))
+	if err != nil {
+		panic(err)
+	}
+}
 
 // The argument for handling.
 type Arg struct {
@@ -15,14 +46,57 @@ type Arg struct {
 }
 type A = Arg
 
+// Changes screen of user to the Id one.
+func (c *Arg) ChangeScreen(screenId ScreenId) error {
+	// Return if it will not change anything.
+	if c.CurrentScreenId == screenId {
+		return nil
+	}
+
+	if !c.B.behaviour.ScreenExist(screenId) {
+		return ScreenNotExistErr
+	}
+
+	// Stop the reading by sending the nil.
+	if c.readingUpdate {
+		c.updates <- nil
+	}
+
+	screen := c.B.behaviour.Screens[screenId]
+	screen.Render(c.Context)
+
+	c.Session.ChangeScreen(screenId)
+	c.KeyboardId = screen.KeyboardId
+
+	if screen.Action != nil {
+		c.run(screen.Action, c.U)
+	}
+
+	return nil
+}
+
+// The argument for handling in group behaviour.
 type GroupArg struct {
-	GroupArg *GroupContext
-	U        *Update
+	*GroupContext
+	*Update
 }
 type GA = GroupArg
 
-type Action interface {
-	Act(*Arg)
+func (a *GA) SentFromSid() SessionId {
+	return SessionId(a.SentFrom().ID)
+}
+
+func (a *GA) GetSessionValue() any {
+	v, _ := a.B.GetSessionValueBySid(a.SentFromSid())
+	return v
+}
+
+// The argument for handling in channenl behaviours.
+type ChannelArg struct {
+}
+type CA = ChannelArg
+type ChannelAction struct {
+	Act (*ChannelArg)
 }
 
 type JsonTyper interface {
@@ -37,23 +111,3 @@ type JsonAction struct {
 func (ja JsonAction) UnmarshalJSON(bts []byte, ptr any) error {
 	return nil
 }
-
-// Customized action for the bot.
-type ActionFunc func(*Arg)
-
-// The type implements changing screen to the underlying ScreenId
-type ScreenChange ScreenId
-
-func (sc ScreenChange) Act(c *Arg) {
-	if !c.B.ScreenExist(ScreenId(sc)) {
-		panic(ScreenNotExistErr)
-	}
-	err := c.ChangeScreen(ScreenId(sc))
-	if err != nil {
-		panic(err)
-	}
-}
-
-func (af ActionFunc) Act(c *Arg) {
-	af(c)
-}
diff --git a/src/tx/beh.go b/src/tx/beh.go
index f96297f..39990f8 100644
--- a/src/tx/beh.go
+++ b/src/tx/beh.go
@@ -3,6 +3,10 @@ package tx
 // The package implements
 // behaviour for the Telegram bots.
 
+// The type describes behaviour for the bot in channels.
+type ChannelBehaviour struct {
+}
+
 // The type describes behaviour for the bot in personal chats.
 type Behaviour struct {
 	Start     Action
@@ -11,18 +15,6 @@ type Behaviour struct {
 	Commands  CommandMap
 }
 
-// The type describes behaviour for the bot in group chats.
-type GroupBehaviour struct {
-	// Will be called on adding the bot to the group.
-	//Add GroupAction
-	// List of commands
-	Commands CommandMap
-}
-
-// The type describes behaviour for the bot in channels.
-type ChannelBehaviour struct {
-}
-
 // Returns new empty behaviour.
 func NewBehaviour() *Behaviour {
 	return &Behaviour{
@@ -128,3 +120,41 @@ func (beh *Behaviour) GetScreen(id ScreenId) *Screen {
 	screen := beh.Screens[id]
 	return screen
 }
+
+// The type describes behaviour for the bot in group chats.
+type GroupBehaviour struct {
+	Init GroupAction
+	// List of commands
+	Commands GroupCommandMap
+}
+
+func NewGroupBehaviour() *GroupBehaviour {
+	return &GroupBehaviour{
+		Commands: make(GroupCommandMap),
+	}
+}
+
+func (b *GroupBehaviour) WithInitAction(a GroupAction) *GroupBehaviour {
+	b.Init = a
+	return b
+}
+
+func (b *GroupBehaviour) InitFunc(fn GroupActionFunc) *GroupBehaviour {
+	return b.WithInitAction(fn)
+}
+
+func (b *GroupBehaviour) WithCommands(
+	cmds ...*GroupCommand,
+) *GroupBehaviour {
+	for _, cmd := range cmds {
+		if cmd.Name == "" {
+			panic("empty command name")
+		}
+		_, ok := b.Commands[cmd.Name]
+		if ok {
+			panic("duplicate command definition")
+		}
+		b.Commands[cmd.Name] = cmd
+	}
+	return b
+}
diff --git a/src/tx/bot.go b/src/tx/bot.go
index 8def42d..e58549e 100644
--- a/src/tx/bot.go
+++ b/src/tx/bot.go
@@ -1,60 +1,113 @@
 package tx
 
 import (
-	"fmt"
+	//"fmt"
+
+	"errors"
 
 	apix "github.com/go-telegram-bot-api/telegram-bot-api/v5"
 )
 
+type Update = apix.Update
+type Chat = apix.Chat
+type User = apix.User
+
 // The wrapper around Telegram API.
 type Bot struct {
 	*apix.BotAPI
-	*Behaviour
-	sessions SessionMap
+	Me *User
+	// Private bot behaviour.
+	behaviour *Behaviour
+	// Group bot behaviour.
+	groupBehaviour *GroupBehaviour
+	// Bot behaviour in channels.
+	channelBehaviour *ChannelBehaviour
+	sessions         SessionMap
+	groupSessions    GroupSessionMap
 }
 
-// Return the new bot for running the Behaviour.
-func NewBot(token string, beh *Behaviour, sessions SessionMap) (*Bot, error) {
+// Return the new bot with empty sessions and behaviour.
+func NewBot(token string) (*Bot, error) {
 	bot, err := apix.NewBotAPI(token)
 	if err != nil {
 		return nil, err
 	}
 
-	// Make new sessions if no current are provided.
-	if sessions == nil {
-		sessions = make(SessionMap)
-	}
-
 	return &Bot{
-		BotAPI:    bot,
-		Behaviour: beh,
-		sessions:  make(SessionMap),
+		BotAPI: bot,
 	}, nil
 }
 
+func (bot *Bot) GetSessionValueBySid(
+	sid SessionId,
+) (any, bool) {
+	v, ok := bot.sessions[sid]
+	return v.V, ok
+}
+
+func (bot *Bot) GetGroupSessionValue(
+	sid SessionId,
+) (any, bool) {
+	v, ok := bot.groupSessions[sid]
+	return v.V, ok
+}
+
+func (b *Bot) WithBehaviour(beh *Behaviour) *Bot {
+	b.behaviour = beh
+	b.sessions = make(SessionMap)
+	return b
+}
+
+func (b *Bot) WithSessions(sessions SessionMap) *Bot {
+	b.sessions = sessions
+	return b
+}
+
+func (b *Bot) WithGroupBehaviour(beh *GroupBehaviour) *Bot {
+	b.groupBehaviour = beh
+	b.groupSessions = make(GroupSessionMap)
+	return b
+}
+
+func (b *Bot) WithGroupSessions(sessions GroupSessionMap) *Bot {
+	b.groupSessions = sessions
+	return b
+}
+
 // Run the bot with the Behaviour.
 func (bot *Bot) Run() error {
+	if bot.behaviour == nil &&
+		bot.groupBehaviour == nil {
+		return errors.New("no behaviour defined")
+	}
 	bot.Debug = true
 	uc := apix.NewUpdate(0)
 	uc.Timeout = 60
 	updates := bot.GetUpdatesChan(uc)
-	privateChans := make(map[SessionId]chan *Update)
-	groupChans := make(map[SessionId]chan *Update)
+	handles := make(map[string]chan *Update)
+
+	if bot.behaviour != nil {
+		chn := make(chan *Update)
+		handles["private"] = chn
+		go bot.handlePrivate(chn)
+	}
+
+	if bot.groupBehaviour != nil {
+		chn := make(chan *Update)
+		handles["group"] = chn
+		handles["supergroup"] = chn
+		go bot.handleGroup(chn)
+	}
+
+	me, _ := bot.GetMe()
+	bot.Me = &me
 	for u := range updates {
-		var chatType string
-
-		if u.Message != nil {
-			chatType = u.Message.Chat.Type
-		} else if u.CallbackQuery != nil {
-			chatType = u.Message.Chat.Type
+		chn, ok := handles[u.FromChat().Type]
+		if !ok {
+			continue
 		}
 
-		switch chatType {
-		case "private":
-			bot.handlePrivate(&u, privateChans)
-		case "group", "supergroup":
-			bot.handleGroup(&u, groupChans)
-		}
+		chn <- &u
 	}
 
 	return nil
@@ -62,55 +115,69 @@ func (bot *Bot) Run() error {
 
 // The function handles updates supposed for the private
 // chat with the bot.
-func (bot *Bot) handlePrivate(u *Update, chans map[SessionId]chan *Update) {
+func (bot *Bot) handlePrivate(updates chan *Update) {
+	chans := make(map[SessionId]chan *Update)
 	var sid SessionId
-	if u.Message != nil {
-		msg := u.Message
-
-		if bot.Debug {
-			fmt.Printf("is command: %q\n", u.Message.IsCommand())
-			fmt.Printf("command itself: %q\n", msg.Command())
-			fmt.Printf("command arguments: %q\n", msg.CommandArguments())
-			fmt.Printf("is to me: %q\n", bot.IsMessageToMe(*msg))
-		}
-
-		// Create new session if the one does not exist
-		// for this user.
-		sid = SessionId(u.Message.Chat.ID)
-		if _, ok := bot.sessions[sid]; !ok {
-			bot.sessions.Add(sid)
-		}
-
-		// The "start" command resets the bot
-		// by executing the Start Action.
-		if u.Message.IsCommand() {
-			cmdName := CommandName(u.Message.Command())
-			if cmdName == "start" {
-				// Getting current session and context.
-				session := bot.sessions[sid]
-				ctx := &Context{
-					B:       bot,
-					Session: session,
-					updates: make(chan *Update),
-				}
-
-				chn := make(chan *Update)
-				chans[sid] = chn
-				// Starting the goroutine for the user.
-				go ctx.handleUpdateChan(chn)
+	for u := range updates {
+		if u.Message != nil {
+			// Create new session if the one does not exist
+			// for this user.
+			sid = SessionId(u.Message.Chat.ID)
+			if _, ok := bot.sessions[sid]; !ok {
+				bot.sessions.Add(sid)
 			}
+
+			// The "start" command resets the bot
+			// by executing the Start Action.
+			if u.Message.IsCommand() {
+				cmdName := CommandName(u.Message.Command())
+				if cmdName == "start" {
+					// Getting current session and context.
+					session := bot.sessions[sid]
+					ctx := &Context{
+						B:       bot,
+						Session: session,
+						updates: make(chan *Update),
+					}
+
+					chn := make(chan *Update)
+					chans[sid] = chn
+					// Starting the goroutine for the user.
+					go ctx.handleUpdateChan(chn)
+				}
+			}
+		} else if u.CallbackQuery != nil {
+			sid = SessionId(u.CallbackQuery.Message.Chat.ID)
+		}
+		chn, ok := chans[sid]
+		// The bot MUST get the "start" command.
+		// It will do nothing otherwise.
+		if ok {
+			chn <- u
 		}
-	} else if u.CallbackQuery != nil {
-		sid = SessionId(u.CallbackQuery.Message.Chat.ID)
 	}
-	chn, ok := chans[sid]
-	// The bot MUST get the "start" command.
-	// It will do nothing otherwise.
-	if ok {
+}
+
+func (bot *Bot) handleGroup(updates chan *Update) {
+	var sid SessionId
+	chans := make(map[SessionId]chan *Update)
+	for u := range updates {
+		sid = SessionId(u.FromChat().ID)
+		// If no session add new.
+		if _, ok := bot.groupSessions[sid]; !ok {
+			bot.groupSessions.Add(sid)
+			session := bot.groupSessions[sid]
+			ctx := &GroupContext{
+				B:            bot,
+				GroupSession: session,
+				updates:      make(chan *Update),
+			}
+			chn := make(chan *Update)
+			chans[sid] = chn
+			go ctx.handleUpdateChan(chn)
+		}
+
+		chn := chans[sid]
 		chn <- u
 	}
 }
-
-// Not implemented yet.
-func (bot *Bot) handleGroup(u *Update, chans map[SessionId]chan *Update) {
-}
diff --git a/src/tx/command.go b/src/tx/command.go
index 58247c7..281280a 100644
--- a/src/tx/command.go
+++ b/src/tx/command.go
@@ -7,28 +7,14 @@ import (
 )
 
 type Message = apix.Message
-
 type CommandName string
 
-type CommandContext struct {
-	// The field declares way to interact with the group chat in
-	// general.
-	*Context
-	Message *Message
-}
-
-type CommandMap map[CommandName]*Command
-
-type CommandHandlerFunc func(*CommandContext)
-type CommandHandler interface {
-	Run(*Context)
-}
-
 type Command struct {
 	Name        CommandName
 	Description string
 	Action      Action
 }
+type CommandMap map[CommandName]*Command
 
 func NewCommand(name CommandName) *Command {
 	return &Command{
@@ -49,3 +35,30 @@ func (c *Command) Desc(desc string) *Command {
 	c.Description = desc
 	return c
 }
+
+type GroupCommand struct {
+	Name        CommandName
+	Description string
+	Action      GroupAction
+}
+type GroupCommandMap map[CommandName]*GroupCommand
+
+func NewGroupCommand(name CommandName) *GroupCommand {
+	return &GroupCommand{
+		Name: name,
+	}
+}
+
+func (cmd *GroupCommand) WithAction(a GroupAction) *GroupCommand {
+	cmd.Action = a
+	return cmd
+}
+
+func (cmd *GroupCommand) ActionFunc(fn GroupActionFunc) *GroupCommand {
+	return cmd.WithAction(fn)
+}
+
+func (cmd *GroupCommand) Desc(desc string) *GroupCommand {
+	cmd.Description = desc
+	return cmd
+}
diff --git a/src/tx/context.go b/src/tx/context.go
index 9c607c4..38e27ca 100644
--- a/src/tx/context.go
+++ b/src/tx/context.go
@@ -17,31 +17,26 @@ type Context struct {
 	readingUpdate bool
 }
 
-// Context for interaction inside groups.
-type GroupContext struct {
-	*GroupSession
-	B *Bot
-}
-
 // Goroutie function to handle each user.
 func (c *Context) handleUpdateChan(updates chan *Update) {
+	var act Action
 	bot := c.B
 	session := c.Session
-	c.run(bot.Start, nil)
+	beh := bot.behaviour
+	c.run(beh.Start, nil)
 	for u := range updates {
-		screen := bot.Screens[session.CurrentScreenId]
+		screen := bot.behaviour.Screens[session.CurrentScreenId]
 		// The part is added to implement custom update handling.
 		if u.Message != nil {
-			var act Action
 			if u.Message.IsCommand() && !c.readingUpdate {
 				cmdName := CommandName(u.Message.Command())
-				cmd, ok := bot.Behaviour.Commands[cmdName]
+				cmd, ok := beh.Commands[cmdName]
 				if ok {
 					act = cmd.Action
 				} else {
 				}
 			} else {
-				kbd := bot.Keyboards[screen.KeyboardId]
+				kbd := beh.Keyboards[screen.KeyboardId]
 				btns := kbd.buttonMap()
 				text := u.Message.Text
 				btn, ok := btns[text]
@@ -65,10 +60,6 @@ func (c *Context) handleUpdateChan(updates chan *Update) {
 					act = btn.Action
 				}
 			}
-
-			if act != nil {
-				c.run(act, u)
-			}
 		} else if u.CallbackQuery != nil {
 			cb := apix.NewCallback(u.CallbackQuery.ID, u.CallbackQuery.Data)
 			data := u.CallbackQuery.Data
@@ -77,49 +68,26 @@ func (c *Context) handleUpdateChan(updates chan *Update) {
 			if err != nil {
 				panic(err)
 			}
-			kbd := bot.Keyboards[screen.InlineKeyboardId]
+			kbd := beh.Keyboards[screen.InlineKeyboardId]
 			btns := kbd.buttonMap()
 			btn, ok := btns[data]
 			if !ok && c.readingUpdate {
 				c.updates <- u
 				continue
 			}
-			c.run(btn.Action, u)
+			act = btn.Action
+		}
+		if act != nil {
+			c.run(act, u)
 		}
 	}
 }
 
 func (c *Context) run(a Action, u *Update) {
-	go a.Act(&A{c, u})
-}
-
-// Changes screen of user to the Id one.
-func (c *Arg) ChangeScreen(screenId ScreenId) error {
-	// Return if it will not change anything.
-	if c.CurrentScreenId == screenId {
-		return nil
-	}
-
-	if !c.B.ScreenExist(screenId) {
-		return ScreenNotExistErr
-	}
-
-	// Stop the reading by sending the nil.
-	if c.readingUpdate {
-		c.updates <- nil
-	}
-
-	screen := c.B.Screens[screenId]
-	screen.Render(c.Context)
-
-	c.Session.ChangeScreen(screenId)
-	c.KeyboardId = screen.KeyboardId
-
-	if screen.Action != nil {
-		c.run(screen.Action, c.U)
-	}
-
-	return nil
+	go a.Act(&A{
+		Context: c,
+		U:       u,
+	})
 }
 
 // Returns the next update ignoring current screen.
@@ -158,3 +126,56 @@ func (c *Context) Send(v ...any) error {
 func (c *Context) Sendf(format string, v ...any) error {
 	return c.Send(fmt.Sprintf(format, v...))
 }
+
+// Context for interaction inside groups.
+type GroupContext struct {
+	*GroupSession
+	B       *Bot
+	updates chan *Update
+}
+
+func (c *GroupContext) run(a GroupAction, u *Update) {
+	go a.Act(&GA{
+		GroupContext: c,
+		Update:       u,
+	})
+}
+
+func (c *GroupContext) handleUpdateChan(updates chan *Update) {
+	var act GroupAction
+	beh := c.B.groupBehaviour
+	for u := range updates {
+		if u.Message != nil {
+			msg := u.Message
+			if msg.IsCommand() {
+				cmdName := CommandName(msg.Command())
+
+				// Skipping the commands sent not to us.
+				atName := msg.CommandWithAt()[len(cmdName)+1:]
+				if c.B.Me.UserName != atName {
+					continue
+				}
+				cmd, ok := beh.Commands[cmdName]
+				if !ok {
+					// Some lack of command handling
+					continue
+				}
+				act = cmd.Action
+			}
+		}
+		if act != nil {
+			c.run(act, u)
+		}
+	}
+}
+
+func (c *GroupContext) Sendf(format string, v ...any) error {
+	return c.Send(fmt.Sprintf(format, v...))
+}
+
+// Sends into the chat specified values converted to strings.
+func (c *GroupContext) Send(v ...any) error {
+	msg := apix.NewMessage(c.Id.ToTelegram(), fmt.Sprint(v...))
+	_, err := c.B.Send(msg)
+	return err
+}
diff --git a/src/tx/screen.go b/src/tx/screen.go
index 9ee0278..0de136b 100644
--- a/src/tx/screen.go
+++ b/src/tx/screen.go
@@ -76,7 +76,7 @@ func (s *Screen) Render(c *Context) error {
 	msg := apix.NewMessage(id, s.Text.String())
 
 	if s.InlineKeyboardId != "" {
-		kbd, ok := c.B.Keyboards[s.InlineKeyboardId]
+		kbd, ok := c.B.behaviour.Keyboards[s.InlineKeyboardId]
 		if !ok {
 			return KeyboardNotExistErr
 		}
@@ -97,7 +97,7 @@ func (s *Screen) Render(c *Context) error {
 
 		// Replace keyboard with the new one.
 		if s.KeyboardId != "" {
-			kbd, ok := c.B.Keyboards[s.KeyboardId]
+			kbd, ok := c.B.behaviour.Keyboards[s.KeyboardId]
 			if !ok {
 				return KeyboardNotExistErr
 			}
diff --git a/src/tx/session.go b/src/tx/session.go
index f4f9a19..66e8d5b 100644
--- a/src/tx/session.go
+++ b/src/tx/session.go
@@ -4,6 +4,11 @@ package tx
 // In fact is simply ID of the chat.
 type SessionId int64
 
+// Convert the SessionId to Telegram API's type.
+func (si SessionId) ToTelegram() int64 {
+	return int64(si)
+}
+
 // The type represents current state of
 // user interaction per each of them.
 type Session struct {
@@ -17,20 +22,6 @@ type Session struct {
 	V          any
 }
 
-// The type represents map of sessions using
-// as key.
-type SessionMap map[SessionId]*Session
-
-// Session information for a group.
-type GroupSession struct {
-	Id SessionId
-	// Information for each user in the group.
-	V map[SessionId]any
-}
-
-// Map for every user in every chat sessions.
-type GroupSessionMap map[SessionId]*GroupSession
-
 // Return new empty session with specified user ID.
 func NewSession(id SessionId) *Session {
 	return &Session{
@@ -39,6 +30,28 @@ func NewSession(id SessionId) *Session {
 	}
 }
 
+// Changes screen of user to the Id one for the session.
+func (c *Session) ChangeScreen(screenId ScreenId) {
+	c.PreviousScreenId = c.CurrentScreenId
+	c.CurrentScreenId = screenId
+}
+
+// The type represents map of sessions using
+// as key.
+type SessionMap map[SessionId]*Session
+
+// Add new empty session by it's ID.
+func (sm SessionMap) Add(sid SessionId) {
+	sm[sid] = NewSession(sid)
+}
+
+// Session information for a group.
+type GroupSession struct {
+	Id SessionId
+	// Information for each user in the group.
+	V map[SessionId]any
+}
+
 // Returns new empty group session with specified group and user IDs.
 func NewGroupSession(id SessionId) *GroupSession {
 	return &GroupSession{
@@ -47,18 +60,9 @@ func NewGroupSession(id SessionId) *GroupSession {
 	}
 }
 
-// Changes screen of user to the Id one for the session.
-func (c *Session) ChangeScreen(screenId ScreenId) {
-	c.PreviousScreenId = c.CurrentScreenId
-	c.CurrentScreenId = screenId
-}
+// Map for every group the bot is in.
+type GroupSessionMap map[SessionId]*GroupSession
 
-// Convert the SessionId to Telegram API's type.
-func (si SessionId) ToTelegram() int64 {
-	return int64(si)
-}
-
-// Add new empty session by it's ID.
-func (sm SessionMap) Add(sid SessionId) {
-	sm[sid] = NewSession(sid)
+func (sm GroupSessionMap) Add(sid SessionId) {
+	sm[sid] = NewGroupSession(sid)
 }