David - we just invited APUG photogers for these shows. The both were posted here on APUG and whoever responded was in the show. It was kinda open submission (open to any APUGer) and kinda selective (open only to APUGers).
We try to do things as a group: shoots; general gatherings; informal workshops... in larger groups or with just two to four people. I think it is great that we try to stay active and involved.