Thanks all for your prompt feedback. I can see how the back end of this could become a cumbersome russian-doll type situation.
For now I think we’ve found a workaround. The plan is to create a parallel collection project to capture all the observations made by students in the course, over the dates of the assignment, and then add that collection project to our institutional umbrella project that track our overall stats. At the end of the course we’ll likely delete the course sub-umbrella used to display the leaderboard of different student groups, and only keep the class collection project to track the stats for the course as a whole. Please chime in if you can see a more elegant solution here.