>>281427467
With udon it's possible to get the name of a player and save it as a string in a local array. 

After each pairing, you client could add your partner's name to a list of people who you've already seen, which would let the world sort people into "fresh" pairings each time without empty rounds. It would also let people join or leave the "pool" of active participants at any time. None of that can be done with the trigger system which is why the current map is predetermined sequences.