Collaborative groups may have 2 or 3 people in them, no more.
Larger groups become too unwieldy.
Then put it away for a while. When you revise and rewrite, your working time should be about 30-60 minutes at most. Please form groups at the beginning of each production commentary assignment. That is, there should be no implicit or explicit commitment to keep working together beyond each individual assignment. In writing production commentaries, the 2 or 3 members of your group must work on each draft.