"I haven’t found a workaround for this yet but I can imagine this would be a game changer if future improvements allow precise blending placement from one image

"I haven’t found a workaround for this yet but I can imagine this would be a game changer if future improvements allow precise blending placement from one image to another." ControlNet allows you to sketch or use a pre-existing sketch to then use as the basis for image generation. Allows for very, ahem, /stable/ variations between different sub-prompts.