c# - Permanent group in xmpp -

i developing chat app in c#.net using jabber, agsxmpp library , want make groupchat in such whatsapp groupchat , skype groupchat.

i came across persistent room in xmpp. provides functionality of permanent groups? , possible creator of persistent group to add members without sending invites them?

i searched xmpp stuff on google, nothing found room use persistent, or should go members only? if yes please explain how.

xmpp groupchat defined in xep-0045: multi-user chat. specification indeed define "persistent room", "a room not destroyed if last occupant exits; antonym: temporary room.".

i think not mean refer whatsapp. in xmpp, muc room based on presence. means can in muc room if have session open , sent presence join muc room. cannot force user join muc room client can send presence join.