I've got a pickle with a company intranet site that appears on our local network at http://intranet and also to some external users at http://intranet.ourdomain.com

The problem is that many of our links are absolute in our node content and legacy HTML/PDF files. When the external user clicks on an absolute link of http://intranet/node/28, they get nothing ... They would need to see it as http://intranet.ourdomain.com/node/28

Is this something that could be easily solved in .htaccess with a rewrite function of some sort?

Drupal is only a portion of this mess. There are thousands of other legacy HTML and PDF files with these absolute links so revising them to relative links would be a nightmare.

(Running Apache 2.2.9/PHP 5.2.6 on Windows Server 2003)

Edit: and I have been looking at http://drupal.org/project/domain but that module would not address our legacy HTML/PDF files so I am hoping a tweak to .htaccess might be the route to cure everything.