Feel free to come down harder on them. As an AFAB in middle school, yeah - we were horrid little things. In my Girl Scout troop meetings, we had troop leaders who would take no gruff.

Are there breakout groups that ever happen? I know that Ingersoll has those; it might be better to have a special breakout group that's just them, so that they can sort out their feelings around gender better in a more isolated spot.

Also, maybe remind them that this is a support group, not a social group. Socializing can be done at another time.