I don't have too much info as I don't do much 70v either, but why is replacing the amp not an option? I understand it is not located in that area. Are you saying that replacing will not give any level of control based on it's location?

I will say that Atlas has a system that is highly configurable and they offer their own keypads that might allow for this. I have no experience with it and cannot give any model numbers. I did see it at a disty expo a short while back and it looked pretty impressive.