It's not an ideal solution (as really there isn't one) but you might be better to do it once watching all the CSs (people won't wait they will just do the bosses as they are all easily done with just four people), and then do it again where you skip the cutscenes with everyone and do the boss fights with them. Like I said, not ideal, but as someone else pointed out at least this is the only content that has this sort of cutscene problem