[2x2 Tournament] Double Up [SoD]

It's been tried before; you need to ask Baratorcha (if he can do it), because you can't restrict it with rules. I've repeatedly tried to come up with a reasonable restriction, but it always turns out to be nonsense. The only option would be to remove the spell from the game, which isn't ideal either.
P.S. If it's possible to edit the spell's action somehow, you could simply make it so that the unit with Berserk attacks the nearest hex.