This is a good idea. When my ex-p-doc wanted me to do the intensive outpatient program, I figured out an alternative plan for myself, including a safety plan, and presented that to ex-T (she hadn't even been in favor of the intensive outpatient to begin with). I think she then talked to ex-p-doc about it. I didn't completely follow that plan ultimately, but I think the act of coming up with one was helpful.

I forget whether your T does EMDR or if you've tried that, but would that be a possibility? That's been much more studied in terms of it helping with trauma and PTSD. I just did a search on DBT and PTSD, and it seems like their hasn't been much research on that yet, and the research that has been done has mainly been on people with and other complex trauma issues stemming from childhood rather than more recent trauma, like the fire. So could EMDR be a possibility?

If you do end up trying the DBT skills group, if you aren't finding it helpful (or if you're finding it triggering and it's making you worse), do you think your T would be understanding if you stopped going? That way you gave it a try. But I also completely understand the desire not to want to go at all, since ex-T once recommended DBT for me since she said I had difficulty regulating my emotions.