I dunno, I think that multiple people doing a workout together in the same at-home room is a bit of an edge case for this app. I have a not-tiny house, and I don't have a space where I could do that without having to move heavy furniture around first. People who live in apartments are really out of luck.

They do support syncing up the workouts of people who're each using their own device: https://support.apple.com/en-us/101979