[RR]

Has there been an established "standard raise?" If there has been and Elder makes this size raise I would compel the third player to raise. If Elder makes some other size of raise I would rule this out of turn action to be non-binding. This is in a perfect world where you are aware of how the action has been going.

A more practical solution would be to rule this third player's action is not binding. I see no way for Elder to be put at a disadvantage from this player not being compelled to call unless he alters his bet size hoping to take advantage of this player intending to call.