Chatroom user restriction question

Through the openfire admin site I can change users into different permissions and that can prevent them from typing into a conference. Now how do I do it so that when users U1,U2,U3 are chatting about something private in the chatroom I make other users in the chatroom to not see the discussion?

thanks

anyone?

I think you can’t achieve that. If user can join a room it will see everything, you can only take a voice ability from him.