I teach TRX group classes as well, 5 straps and varying participants. I usually have participants pair up, and while one person is doing a TRX exercise the other person is doing a complimentary exercise off the strap. I usually have each exercise last between 30sec and 1 minute.
Then I also throw in a group exercise where all participants are doing the same exercise at once (a non-TRX exercise), like walking lunges, burpees, inchworm, sit ups and so on.
Hope this helps!