You have a model with 3 demes, with the deme having the lowest proportion of A-individuals being killed. This is no different from a model with 3 individuals wi

You have a model with 3 demes, with the deme having the lowest proportion of A-individuals being killed. This is no different from a model with 3 individuals with the individual with the lowest number of A-alleles being killed. You can, of course, give a narrative argument on why you feel it is justified to exclude the interplay between these levels. But if you, at some point, try to show it is justified, by removing the assumption from your model, you'll struggle, I predict. Evolving systems are very complex, it is an unwise assumption that you can chunk their dynamics into levels of abstraction and expect those dynamics to function independently or predictably when combined.