I can't really help as I have the same problem with my three ladies. Athena is the chaser and the eldest by a few months.
I have put her in the lower cage only to have the others miss her and look for her.
I put 2 food trays in different locations; doesn't matter she goes there as well and still chases.
I am still in search of answers on how to prevent this but for now, I just let her be the alpha. The vets says they are all healthy.