My leaderboard works, and i am trying now to be able to eliminate choices when they were selected before, in my different leaderboards (like party). 
I am trying to use your method : How to eliminate choices after they've been selected: Many-to-many relations)
But i can’t figured out how to turn that pattern : email - team1 to that pattern : email - team 1 - leaderboard (here in your tuto)
We would need some leaderboard dynamics data i guess.
Any idea ? 
Maybe another challenge for @Robert_Petitto = Glide god! 