You can change the family instance var for each object. If you click the object you will see it inherits the family instance variable and you can change it to fit each object of the family. Just remember you change the value in the Main Family it will reset the objects. I am using this way for a Customer Family and each customer have a certain patience level. So the instance variable is the default variable but you can override in each object.
[attachment=1:2lfkl4en][/attachment:2lfkl4en]
[attachment=0:2lfkl4en][/attachment:2lfkl4en] Now I can override what the object inherited from the Customer Family .