Way back when I transitioned, I didn't do group therapy (not available), but I did go to a weekly peer-led support group, and it was an amazingly positive and supportive time for me. Being with other people in person who are going through the same thing, getting to share mutual experiences, seeing how various people are getting along with the physical aspects of transition, getting references to better local doctors, therapists, stores, electrologists and such, it was all so vital for me at the time. These people were my social life for about two years, and I don't think I could have done it without them.
Now, sure, there were times that weren't all that wonderful. A bunch of self-involved people with virtually nothing else in common, many with severe behavioral and psychological issues beyond the scope of our amateur facilitation, and sometimes it got very intense with some who you couldn't do anything for (because they needed so much more than a shoulder to cry on), and being immersed in a world of dysphoria can kick up dysphoria, yeah, not all peaches and cream.
That said, overall, I'd probably be dead now if it wasn't for that support group back in the day.