I know this will likely never be an option but for some reason I've had the thought of a possibility where you can invite multiple people down into the private dungeon at once
You can (kinda) if u leave one and go to another... i assume tho u mean having interactions, which isnt in game. But it could be fun. Especially with cassie and alissa
It's actually planned for certain NPC combinations to have special scenes (like if you leave Cassie on the bed, then bring Alissa, they might do something.) But I need to finish all the individual private dungeon scenes first, and it only gets worse as I add more NPCs/equipment