EDIT: Already Possible - Discounts by Total Classes Per Family

Edit: This is already possible by setting Tuition calculation to "Add up Classes and hours by Family" under Tuition & Statements -> Calculation

Our studio currently offers discounts based on the total number of classes per family. To give an example, if a family has two students, one of which takes one class, the other of which takes two, we would like to be able to give a discount based on the total number of classes between the two instead of only the student with two classes receiving a discount.