My BFF Sewing friend comes to sew quite frequently. I have to admit that i don't get much of my own sewing done, as over the last 2 years, I've taught her to quilt. It's gotten better lately, but I still can't focus much on my own projects. I've just learned to enjoy the time together, and try to work together on a project.
I also quilt once per month with a larger group of ladies in a church fellowship hall. While I truly enjoy this group, I find I get about 30 minutes of sewing done in 6 hours. Between set up, show and tell, social time catching up with each of the ladies and lunch, I really should just leave my machine at home and bring some hand stitching.
When I go to retreats, I try to be very project focussed as I'm paying a certain amount of money for the hours of sewing time. Thinking that way helps me to focus on projects.
While I get little done in a group setting, I find that I really enjoy being part of a community of quilters. The trade offs are worth it, in my opinion.