Roles and permissions management with custom API

We planned to use Auth0 on many connected websites to manage roles and permissions. Roles will be the same for each website ([“super-admin”, “admin”, “super-user”, “user”, “viewer”]), but permissions should differ from a website to another ({viewer: [“read:project” (API-A), “read:service” (API-B)]}). We created a separated Applications and API by website in the Auth0 settings.

We are able to get permissions of a user according to his role regarding the API assigned to the application. When we load the role list with their permissions, we get the list of permissions of all API. Is it possible to get only permissions from one API or to identify permissions to its API when loading the role list?

Also, permissions will differ from a project to another on the same website (application). Is there a way and what is the best way to achieve that using Auth0?