Create Ability to Group students in a Family and charge a "Family Fee"

Sometimes at our Academy a family of 4+ students enters. At OUR Academy, we feel like setting a 'cap' on the total tuition per month. It would be great if we could have the ability to check a box on a parent of a group of students that might say "[] Use Family Rates for all students in this family". Then in the tuition section, we could set up a Family rate or different ones based on how many family members there are: maybe if there are 4-5 students, the total tuition per month might be set at $250. But if Mom and Dad start taking, that means 6-7 students so that might be $350/month.

Along with setting tuition limits based on student groups, it woud be helpful if we could then designate certain classes as being assignable to Family Rates - or not. There might be a special workshop or class that no matter what needs to be charged or paid for. So setting that class to Not Assignable or just not clicking [] Family Rates can apply is sufficient.