Nextcloud user-logins from different database


I have set up an instance from Nextcloud 12 and i really like it.
Now I want to use it on my server, on which i also have multiple other services with logins. I have an extra table for users and their password-hashes. All different systems use this data for user authentication. I would like to setup Nextcloud to use this user-table, too. Is this possible, and if yes, how?

Thank you for your help,

If I understand correctly, you want Nextcloud to authenticate against your custom user database? It sounds like you’ll need to write a custom Nextcloud app for that.
I would start here: and also look at this: