The best thing to do is remove all of the nests or houses. When you have more than one pair in a cage, you can’t allow any breeding. They do not do well if you try to breed them in a colony in captivity. It causes the birds to be more territorial, and the fighting will only get worse when they start laying eggs. Every pair of birds are rivals to each other. If a single bird or pair doesn’t get away quickly enough, they could be killed by another pair. Once eggs are laid, the pairs are likely to try to raid each other’s nests and will destroy eggs or even kill chicks. You have no control over which birds breed, and one male could become dominant and mate with all of the females. Any chicks that manage to fledge will be in danger from other adult birds. If you want to breed, you have to separate each pair to their own cage. Remove the nests/houses and you should soon observe nothing more than occasional harmless sparring. Of course always have multiple feeding stations so the birds do not fight over food and water.
Thank you for asking Lafeber,