Presumably if you set up the same kit but with ants of the same species then they wouldn't fight and just go about their business? Then I suggest a similar version of this based on capture the flag. You have your same species ant farms connected to a central hub, in that hub you drop something the ants like and can eat and carry, say coloured rice krispies. You either drop one in and whichever colony gets it back to their base after a time period wins, or you drop a load in and tot up how many make it back to each base, the base with the most wins. This way it is less cruel and you won't need to replace your colonies.