weight between [0.8 ,1], start with 1
prompt : fusion dance, fingers together, index finger raised, index finger together, index contact
'Regional prompt extension' looks not mandatory with illustriousXL, but i share the article that made FallenIncursio on that : https://civitai.com/models/339604/how-to-generate-multiple-different-characters-mix-characters-andor-minimize-color-contamination-or-regional-prompt-adetailer-and-inpaint-or-my-workflow
If you use it you will need to reduce weight by half so 0.5 and use 'BREAK' tag for separate the different character.