Stuart,
If you are still using the Auth0 terraform provider and are still in need of this feature I would ask that you raise it with your account manager. I would like to see Auth0 provide an official terraform provider that provides full feature parity with the Auth0 UI and is kept in sync as new features are developed. If you are a paying customer please raise this as a requirement with your account manager so that internal resources can be allocated and a commitment made
regards
Andrew