I have a project that has two applications. A react native user app and an admin website were created using React JS. Both apps should use the same database, which can easily be done in firebase. Now I want to build an Authentication for both apps. But if you register in one app (eg. user app) you should not have an account in the admin app. So I don't know how to handle this problem in Firebase because all apps in one project build on the same Authentication-System. What is the best way to handle this problem?