Millipora IS Acropora. Millipora is the specie, Acropora is the genus. Montipora is a genus too.
Examples: Acropora millipora. Montipora digitata, Montipora capricornus, etc.
Having said that, it would depend on which species you have, and what they are doing battle with. Not all species within a genus, behave similarly.
Jenn