I am working with Doctors who are affiliated with multiple hospitals, which are all in a family of hospitals. How do we link the doctors with each hospital, if they can only be under one account.

Ex:

Happy Hospital has 4 hospitals

a, b, c and d which we have all made into their own accounts.

Dr Y works at a,b, and c

How can I link Dr Y with all 3 so when I search him, I can see he's at 3 of them, without putting him in the system 3 different times under each account.