AA for over 12 yrs - but I wouldn't call it a "support group." I suppose it could look like it is but in recovery I have NOTfound (and even the AA program / book agrees) that my my sobriety and my recovery is in any way, shape or form dependent or contingent upon the actions of others - whether they're supportive or destructive - it's irrelevant.
In AA the individual is responsible for their recovery - period. And yeah, i know that's not the message that a lot of ppl hear at a meeting - but one has to remember - anyone can attend AA and you can say just about anything you want. Unfortunately, even today (depending upon the meeting I go to) most of what I hear is the complete opposite of the actual AA message.