XMPP MUC - Is it possible to disable some feature to do this?

I have one room with two users.

I want that only moderator of the room knows the members-list.

Now, if the member (not moderator) sends something like this:

<iq type='get' from='user@domain/user' to='room@conference.domain/room' xmlns='jabber:client' id='1:sendIQ'><query xmlns='http://jabber.org/protocol/muc#admin'><item affiliation='member'/></query></iq>

or

<iq type='get' from='user@domain/user' to='room@conference.domain/room' xmlns='jabber:client' id='1:sendIQ'><query xmlns='http://jabber.org/protocol/muc#admin'><item affiliation='owner'/></query></iq>

the member could know the list and the jid's of the users, I want to keep it private that information.

Thanks in advance.