My current thinking is that for multiplayer tournaments that last 2 to 10 minutes, I would associate the competing players via a Group Entity. Then when the tournament is over the Group Entity data is useless.
At this point I see two possible approaches:
1. Just delete the Group Entity when the tournament ends. Create new for a new tournament.
2. Keep a pool of Group Entities and recycle them. When a tournament ends I clean the Group Entity and put it into an available pool that supplies recycled Group Entities as new tournaments start.
It seems like 2. would be less overhead on the systems (no allocate/delete). But, I can image a lot of factors that could come into play, many of which I could be unaware.