A class diagram for checking total shares

I have two classes in my application (designed by myself!):
1) estate
2) owner
Here's the problem: an estate can have several owners with different shares and the total share must be 100 percent. I want to check in estate.owners setter to be sure that the total share is 100 percent! ( in the other words if the total share is'n 100%, the owners won't be set!). I want to know if there is any known design pattern for my problem? or any one has ever faced it?