An improved loRA, made by NakedSexiesForTheWin
https://civitai.com/models/85916/conjoined
You may have to push the LoRA a little harder in txt2txt and tone it down in img2img. I've had moderate success with transformix model, but haven't tried it with others. Using "2 girls" instead of "girl" can help make the heads distinct, but can end up adding extra legs.
