How to stop teaming using Ox

It's not making the game complicated. Standard FFA would still exist all the same. I thought adding this one as a variant option, but playing either Ox FFA or Standard FFA it would still have the same leaderboard. I highly doubt that high rated players would join an Ox game at all, it's just a variant for fun, if you don't want to get betrayed in the 4 player stage. Still, I don't know if making a code for this is possible. Currently we have the code for Ox but it lasts the whole game. I just wondered if it's possible...if we can restrict it somehow, to make it more useful...
We can experiment with O(-x2) and/or O(-x10) It only works for the 4 player stage, so idk if it's possible to make (the default version of this option) to last only until someone reaches 20 points or until we reach the 40 moves. It's only the question what rating system to use. I would try Solo with either default +20 promotion 8th or +10 promotion 11th
I would like to try O(-x10) because you can get your opposite mated with capturing only 1 pawn, so no one would do it for the cost of -10 and not knowing if it will result into a checkmate even.