Questions for larger stores Z rapids

Stores that don’t follow the one at a time process for Z rapids, how does it work for you? How do you not end up with all team members in the department shopping rapids? I’ve tried shopping multiple at a time and it seems like the system just allows all rapids to drop in regardless of the current amount of rapids currently in queue. How do you manage this around the other waves that have to be shopped?

I know a few that operate this way, just not sure how it is managed

Also how does the system work overall, and what does DEC stand for?