Page At One URL Using The Cached Page From Another URL?

I'm pretty new to ASP.NET and very new to the concept of caching.

Using MCMS 2002, I built a template.aspx page that receives a "person_id" query string and builds pages accordingly. Several different departments at the school where I work are using this template to display faculty biographies. This much is all working correctly.

The Problem

The problems start happening when I try caching the page. When a person visits person_id=16175 on one department's page, then visits the same numeric bio on a different department page, it loads the cached page instead of rebuilding it. The problem, then, is that it has all of the wrong department branding. For example:

[URL]

It's the same person_id, but the URLs are obviously different. It would be great if the template would recognize the different URLs and ignore the cache. I'm assuming that the problem lies in the fact that both pages are being built using the same aspx page on the backend. Here's the OutputCache bit from the aspx page:

<%@ OutputCache Duration="86400" Location="Server" VaryByParam="person_id; section" VaryByCustom="CMSPosting" VaryByHeader="Referer" %>

I assume I'm doing something wrong here. Hopefully it will be obvious to someone who knows that they're doing. If you need more info, don't hesitate to ask.