Micro-site within login area

I have a client really wanting to use the user accounts already set up with their wordpress site, for logging into a “employees only” section of the site.

I’m wondering what the best way of doing this would be. Can you, for instance, limit what the employees would see when logging in, and hack some of the core files to show new content for them in place of the dashboard?

All that is needed internally is a list of resource links, and an internal news feed.

Any help or advice on this/better alternatives would be greatly appreciated!