What tables do you have?
If you set up these tables/relationships:
Families::FamilyID = Students::FamilyID
Families::FamilyID = Payments::FamilyID
You can enter family data, such as an address once in the family table and just enter student specific data such as name, gender and age in the students table.
Payments can be linked to Families in much the same way.
Instead of the individual payment fields like you show in your screen shot, you'd use a portal to Students and another portal to payments on your families layout to list all students in one portal and all payments in the other.