Hide users not created by a user

Hello all,

For a multi-tenant database system, it is assumed that only databases
and users
created by a certain tenant should be accessible/viewable to him.

From what I read, postgresql stores database and user information in
catalogs that
are accessible to public.

Here is a scenario:

Let's say Tenant A created a database and a set of users, and Tenant B also
does the same in the same postgresql instance.

Can postgresql limit the access/view to only those databases and users
that Tenant A
created?

Any idea on how this could be done?

Thanks and best regards.