Storing 2 players as "pairs"

Trying to find a way to select a person and execute a command as them while using a partner player as an arg in a command (non-vanilla cmd). So like we have a bunch of players in groups of 2, and be able to have anyone run a command for them and their pairs on actions like death and whatnot. I cant use teams since im using them for something else, 1.21. Tried storing uuids in data storage but mc stores uuids in a weird way and i cant use a macro to put their uuid in the command, or at least couldnt figure that out.