Just to be clear, this took a lot of time… My process was like this:
Generate a prompt in R34 merged with F222 (I think it generates more consistently group pictures then just F222), then take the best output and iterate with img2img in F222. Some inpainting to change hair colors/ethnicity etc., since all girls were mostly the same at first. Then upscale, which messed up some of the the details (mostly faces and nipples), so I cut out individual upper bodies in photoshop and did inpainting on them, and then pasted them back into the full picture. Very time consuming, but super happy with the result!