XMPP integration with chat (have the protocol be tied to an XMPP server)
I still really want this one. Or integration to Rocket would be even better.
Is there any off-the-shelf solution to restrict a plugin for a set of group? Or any "easy" solution to do such?
Not really, no. It is up to the plugin itself to support restriction by group. Which plugin were you referring to?
basically the question popped while thinking of installing plugin-adsense (which does not worked at all for me btw - 1.11.2)