I run a Healthy Leaders group and last year I co lead a small group of girls being raised by only their dads.
First step is getting the Principal on board. If your district is as strict as ours there might be a few extra hoops, for the small group of girls we needed to pick a time where the students wouldn't be missing a significant amount of class because holding it before or after school made it "less inclusive" because not everyone has transportation to come early/say late.
I LOVE my Healthy leaders. We talk about how to call 911, how to make sure the "scene is safe" before going to help someone, helping new students find my office and the difference between being sick and being uncomfortable.