I have been to three kinds of support groups run by therapists.
I have been to a group where people talk about the trauma in open ended process groups. I have been to a group where people don't talk about the trauma in specifics as a rule for the group (so people didn't get triggered a lot) but they do talk about skills to cope or challenges to recovery. I have also been to a group that was a mix of both.
The skills based groups (with a focus on learning DBT, CBT, or other skills to manage symptoms) have been both outpatient and inpatient. They tend to be very boundaried and structured to make sure it wasn't destabilizing for people. The skills based group therapy usually make sure there is space for all to talk, and tend to hold boundaries better. Even when I did art therapy as a group, which is fairly open ended, it was still focused on a specific task and goal, and all were heard.
The open ended process groups, where one person could use even the entire time, tended to be very triggering for me for many reasons. A lot more relational challenges seems to come up in them for many people. I could only do them on an on-going basis when I was in a intensive inpatient PTSD program. In that setting, we were encouraged to walk out at any time, and process with staff what was bothering us. They never told us we could walk out of skills groups, but only the open ended process group - it's that well known to be destabilizing.
For me, I was triggered by the therapist herself in those groups and I walked out and processed through it. It was really hard. I wanted the support, but it was too much for me to do at the time on an outpatient basis.
Plus, like all therapies, there are also therapists who do it well, and those who don't.
I'm impressed with how hard you are working to get more support and make this work. You are right that it's not a good thing to leave so destabilized you are suicidal. It may simply not be the right type of group therapy or therapist. It might be more helpful to look into a different kind of group therapy, or a different group therapist that is better skilled at holding the space for everyone in the group better.