[keycloak-user] Bind user to another

Hello, is there a way to bind one user to another (e.g. for impersonation, query, …)? Example: 4 users in one realm: user-a, user-b, user-c, user-d * user-c should be able to impersonate into user-a, but not into user-b. * user-d should be able to impersonate and query all users It would be also very cool, if one user is able to remove the binding. Thanks in advance! Cheers Stefan