title: In Keycloak is there a way to restrict registration for a specific email domains
body: <p>We are building a POC using keycloak server for IAM. The plan is to use realm to seperate out users for different client organizations.</p>
  
  <p>We want to make sure that users registering for a domain can only do so if they have the company's email id. </p>
  
  <p>How do acheive this? Is there a way that we can limit user registration with email id ending with <code>@abc.com</code> to register for a realm.</p>
  
  <p>We are using <strong>4.0.0.beta2</strong> for the poc.</p>