Print For Browser and Operating System

I'm looking for a script that will allow me to print two different HTML segments dependant on the browser version, type and operating system. I want it to show up using a DHTML version on some systems and static HTML on others.

The detection would work as follows:

HTML One Segment (DHTML)
Internet Explorer 4.0+ Windows
Netscape 4.0+ Windows
Netscape 4.0+ Macintosh

HTML Two Segment (HTML)
Internet Explorer 4.0 Macintosh
Netscape 6.0 All operating systems
All 3.0 browsers and any other browser

I used to have a script that worked this way though it included a separate segments for each browser version and operating system combination. If anyone has any ideas I'd appreciate it. I just started researching this but haven't found much yet (particularly when it comes to Netscape 6). I'm on a schedule so I figured I'd post right away.

Thanks!