Group Chat Rooms list by access permission

I’m writing an application using XMPP which needs to know about all group chat rooms the current user has access to. I can simulate this by performing a discovery/items call (disco#items) against the conference server and then send presence to each room while checking the server responses to see if I’m entitled to enter the room. This is obviously a bit of a hack and ideally I’d want to get an initial listing which just has my permitted rooms in it. Does anyone know if this can be done today, or a way to extend the server/protocol to implement it?