You could set the room to not 'public'

 

When a room is not public , that does not mean the room not to be listed .

A not public room means a moderated room . Any other user get in the room should be moderated by the room admin first .

 

For example , you set the room 'A' not public , and you get in the room .

When another user try to get in that room , you will get a message :

" UserX is trying to get in this room , [Accept] or [Reject] "

You could decide it .

 

And , if there is not any room admin in that room ,

The UserX would get a error message automatically :

"No room moderator here!"

 

Please have a try on it .

 

Regards , Terry .