Bunny Spider

Hello! My middle school wants me to produce a Broadway Jr. play without any after school rehearsals until the final week. Students would rehearse within their 45 minute theatre class and each class would have its own cast. Classes meet every other day. I know lots of schools do things this way, but I have limited experience with this sort of schedule and wonder if anyone can share with me how it works? Do you have students play the ensemble in all shows, or only their class's show? I'm told that the previous teacher had great success using this system. Thanks very much!