Well you make it a menu button associated with a key: pressed OR released

steps:
1: all target me > Box A
2: round robin spell > All Boxes (except really only one because of round robin)


That would take up 6 hotkeys, one per character and one for round robining the spell (target me is something isboxer already has as an action). Someone else might be able to come up with a more efficient way to handle it, however.