I'm having problems figuring out how/if I can set up the following with DNN 4.x:

-  I have 6 domains:
domainA.com
domainA.net
domainB.com
domainB.net
domainC.com
domainC.net

-  All 6 domains point to the same single IIS virtual directory on my host, and share the same IP address

-  I want to have 3 'sites', where each site will have different pages, content and skins, but the same shared user database (and forums):
SiteA
SiteB
SiteC

If the user browses to http://DomainA.com or http://DomanA.net, they should see the SiteA content.  (It's fine if the URL they see is something like http://DomainA.com/SiteA/ or http://DomainA.net/SiteA, as long as the displayed URL includes the http://DomainA.* part).  Likewise if they go to http://DomainB.com, they'll see the SiteB content (and may be redirected to a URL like http://DomainB/SiteB).

I don't know how (or if I can) set this up in DNN 4.x.  I think if I try to set up different portals, then I won't get a shared user database.  I can't see a place in DNN to set up a redirect for someone to a particular subfolder/page depending on the domain they used when browsing to the site.

Thanks for any help.