I go to an ftm group and a mixed group which mtf, ftm, genderqueer, parents, spouses, etc all go to. They never assume anything about anybody's gender and ask what pronouns people want to use. When I started, I tried "they" since like AG I considered myself genderqueer. I changed to he later. I could have come in as a she and changed to he later on. OTOH, I suppose things are a bit different if you go to a strictly mtf or ftm group. I actually didn't go to the ftm group until later.
Every so often we have a new person coming to group, coming in looking completely one sex and then see that person become more of what they should be.
--Jay