how to implement feature - superuser shares data to subusers

Hi I'm trying figure out the best way to implement a feature where the superuser has some data (ex: contacts with name, phone number, etc) and can share it with designated subusers. A bonus would be superusers would have read/write access but the subusers would only have read access.

Wondering if this is a database, backend, or frontend problem.

Right now what I'm thinking is in the User Table, have a foreign key of superuser_id to establish superuser and subuser. Then I'm quite confused how to set up the data.

Also any common keywords or phrases used in the industry for this would be helpful for my google search. Thank you!