This may sound funny, but I have social anxiety when it comes to being in group therapy!  One group I was in, it took a couple of years before I felt comfortable enough to talk voluntarily, but as the group dwindled in size, it got easier and now a couple of my closest friends are the ones I made there.  It was pointed out to me that a group kind of replicates our family and that we will often interact in similar ways that we did with them and then it made sense.  All of us in the group had been badly hurt by our families and did not have good relationships with parents or siblings, so it became a good learning experience to figure out how to nurture relationships and get our needs met without having to be angry about it or afraid.  It made sense to me, then, that when the groups got smaller, I felt more comfortable - less likely to feel "ganged up" on.

Maybe if a person can figure out just what situations are the least uncomfortable in which to interact, it would make it a little less frightening.  Maybe just one person at a time, or maybe you feel safer in a larger group for whatever reason.  But it's totally worth it to make the effort!