Does gitlab support organization federation?

We want to self-host gitlab, and also want to use our current company user’s credentials without extra user registration work on gitlab, is it supported on gitlab now?
If it is, where can we get the status from gitlab api? I checked the api there is a section:

GET /users

"identities": [
      {"provider": "github", "extern_uid": "2435223452345"},
      {"provider": "bitbucket", "extern_uid": "john.smith"},
      {"provider": "google_oauth2", "extern_uid": "8776128412476123468721346"}

I think it’s much more just SSO.