Re-using Contacts in different families with different realtionship

What if a father of one student is the stepfather of another one? or an emergency contact for one student is just a friend of the parents but she is also a mother of another student?

We have contacts that are related to other families in a way that it would be too much work and cause major discrepancies with our integrated systems if we just use the private contact feature.

We would love to be able to "search” when adding a contact and associate for example the father of student 1 as the Uncle of student 2. Currently, we have to list this person twice on both students, one as the father of student 1 and one as the uncle of student 2, and then hide the father from student 2, leave uncle, and hide uncle from student 1, leave father. This is so time consuming and when updating a phone number or email address, if you do not see the father in the other record (a random employee could be making this update and not know the relationship to the other) they might forget to update both contacts. We believe that if there was a “pool” of contacts, we could add the father to the second student, and associate him as the uncle. But using the same person's record. Our school cannot use the parents contact type so we have to use father, mother, etc. This is a feature that would help with consistency when updating a phone number or email address for one person that is linked to different students. We have quite a few cases like this, as our students are mainly international and they live in USA with family relatives that often have their students enrolled in our school as well.

Thank you