How to use auth0 token data in Grafana variable dropdown

Question

I have set up a Grafana instance and connected it with the oauth_generix provider to auth0.com. All works fine, group and role sync is working as well. I have > 1000 users in auth0 and each has his own data to view (separated by a user id).

What I now want to do is get the values from auth0 inside a variable dropdown. Each user has a (or some) unique id and can only see data connected to his id. In auth0 I have the following app_metadata defined:

{
  "parameters": {
    "CnNumber": [
      "16992801"
    ]
  },
  ...
}

And this translates in Grafana getting the info like this:

{
  ...
  "https://<domain>/parameters":
  {
    "CnNumber":["16992801"]
  }
}

In the variable settings page I can't find any way of doing this (no auth data source, no variable type, ...) so does anyone know if this is possible?

If this is not possible, I hope I can fix this by creating a custom data source that can read the auth data. Not sure if that will work, but I will give it a try if there is no other option available.

Thanks in advance!