Central User Database Across Multiple Forum Installs

[Elliot McGucken]

Hello Wisher!

I'm wishing for the same hack--here is how I phrased it:

Hello, suppose I wanted to run five different instances of vbulletin on five different domains.

I understand I would need five separate licenses.

What would be the best way to consolidate the user base for all five forums in a single forum?

Basically, if anyone registered at any one of the five forums, I would want them to be able to login with the same user information at any of the other five forums.

I searched, but could not find an answer--I apologize if I missed it.

Please advise. Links or info would be very much appreciated!

Thanks!

--Elliot