http://www.nationalmgc.org/
There are a couple of threads here that may be helpful, I'm trying to locate them right now.
As far as the integration aspect, I was referring to events hosted by the school. My university has freshman groups that group certain students based on major, interest, etc. There are also mentor/mentee programs and "college survival" workshops help throughout the year.
The other programs that you're proposing seem like they'd be very helpful. And yes, I've run across several organizations that offer programs like those.
As soon as I find those threads I mentioned earlier, I'll post the links here for you.