You're probably right, Barry (although I don't know how good a scroundle sounds with a guitar *g*).   
I guess if I sign up I could put a little note beside my name saying "would like to do group." I'm shy about asking people to join me, since it feels I'm putting them on the spot and if a bunch of people say no, it's hard not to feel rejected even though they may have very legitimate reasons for passing (such as they want to do their own solo or other band thing and people are supposed to perform only once).   
I don't mean to make it sound like that big a deal, but sometimes there are several people just itching to do a duo or trio but not happening to connect with each other. Kind of like being at a party where there's a band and not knowing who wants dance partners and who doesn't.
One idea: Will there be any sort of message board, where people can post notes like "looking for carpool home" or "looking for band members for concert?"   

Genie