[Alpertinator]

Oh yeah I like what you said in your point A, that works. If anybody gets too distressed they could be taken to the small task room and filled in.

Or hey, maybe at the start of the task take 3 or 4 random housemates and put them in the small task room for the duriation (courtesy of John James) of the task. And the other housemates have no idea where they've gone.

Or they could start the task with all housemates, but at times when a certain housemate is alone in an area of the house near an exit (garden, wardrobe etc.) they take that housemate to the small task room then... it's complex. Unfortunately this great idea probably won't be done.