I'm not sure if this is possible but here is a brief scenario followed by the question....
Free email addresses are blocked on our forum for registration purposes in order to keep down the many spammers and unwanted. However, daily I receive emails from people asking what they need to do to register as they only have Hotmail, Yahoo, GMail, etc, addresses

I have a dedicated server and occasionally set up an email alias using my domain name and their member number, pointing to their free email address, ie 18974@mydomain.com aliased to theirname@freemailaddress.com . However this is time consuming and relies on my time to do so.
Question: Is there any software out there that can be setup on a server (Windows) that I can use so that I can email a link to the prospective member and from which they could set up their own email alias using one of our domain names? Or is this not possible to do?
Thanks,

Dave