I have 4 zones. Two of these cover the same piece of ground. One zone has pgm sprayers and the other zone has regular sprayers .But they cover exactly the same area. How do I tell the app this so that it knows that running the sprinklers for one zone waters the same trees and grass as the other zone? 

To try and clarify the question - these zones cover the same physical piece of ground, (they overlap 100%) but netro doesn't know that, so it will water one zone and think the other zone is still in need of watering - and thus water the same grass twice. (each zone once so the same grass twice).  Netro's algorithm for determining soil moisture levels can't work if it doesn't realize these two zones are the same physical piece of grass.