This setting is found at:
Configuration -> System Setup -> Price Matrix
Enable Global Family Discount
If you want to give a percentage discount to ALL students in a family when they have a certain number of students or more, tick this box so that you can configure your Global Discount.
For example, you give a 10% discount to ALL enrolled students in a family if a family has 3 or more students.
If you do not give a percentage discount to all students, do not enable this option, rather build the discounting into your price levels.
ON / Enabled
When enabled, the "Family Discount Matrix" is available on your main Configuration screen to set up your global percentage discount.
OFF / Disabled
When disabled, the "Family Discount Matrix" is not available on your main Configuration screen.