one installation split across mutiple subdomains (beta testers needed)

[pavemen]

should be as simple as changing

$mybb->settings['portal_announcementsfid'] = "x,y,z";

based on the FIDs accessible to the subdomain.

Might be a little more to code, but in general the concept is simple but implementing may take some more work.

[Skorm92]

Isn't there a way to replace {$announcements} on the portal template to something like ($mybb->settings['portal_announcementsfid'] = "2"?