There are two easy ways to handle this that I can think of, both require “pairs” in the orgy, no trios.
1) Closest other play is your partner (move around to change partners, somewhat hard to be sure who you're going to play with)
2) Use selection (like the PM box) to choose who you are going to play with (can sometimes require the couple to be brought together, “jumped” into action range)
But once either (or both) method(s) are implemented, then the orgy can work.
PS. This gets rid of the need for threesome “spectator” modes (A+B are acting while C is on couch) and opens up rooms to be able to be set public for dynamic spectators and/or joining.