[keycloak-user] restricting user registration?

[Wyllys Ingersoll]

Is it possible to configure user self-registration to a new realm such that
only users with specific token or link can register?

We want to allow self-registration, but do not want it to be open-ended,
but rather by invitation where the invitation would be an email or some OOB
mechanism that provides the user with a unique 1-time-only code to use to
authorize their registration.

Is this possible?

Thanks,
 Wyllys Ingersoll