When I am grouping livestock into a camp, I want to be able to set a bull to cow ratio. Say, 1 bull for 25 cows, the system should be alert the user to add or reduce the bull. Where and how do I enforce it? I would imagine that this would be the same for the teacher to student ratio. How do I become specific with a "one-many relationship": ie. "one-two" or "one - five" etc.