@Nullable
    public MultiUserChatService getMultiUserChatService(@Nonnull final JID jid) {
        final String subdomain = jid.getDomain().replace("."+ XMPPServer.getInstance().getServerInfo().getXMPPDomain(), "");
        return getMultiUserChatService(subdomain);
    }
Retrieves a MultiUserChatService instance specified by any JID that refers to it. In other words: the argument
value can be a XMPP domain name for the service, a room JID, or even the JID of a occupant of the room. The
implementation takes the domain part of the JID, strips off the server domain name from the end, leaving only the
subdomain, and then calls the subdomain version of the call.

@param jid JID that contains a reference to the conference service.
@return The MultiUserChatService instance associated with the JID, or null if none found.
xmppserver/src/main/java/org/jivesoftware/openfire/muc/MultiUserChatManager.java