ignore part of URL to force caching?

[AJ Weber]

I would like to "override" the intent of the app server that is 
basically disabling any caching of the backend file.  For example, they 
are embedding a "noCache=#######" parameter at the end of the URL (there 
are other parameters following, but if I can check the url up-to the "?" 
that would suit me fine).

This is actually a dynamically generated SWF file, but the file is then 
constant for a reasonable amount of time such that I'd like to cache it 
for a few minutes.

Is there a way in a specific "location" to tell nginx to ignore the 
parameters (or any portion of the URL) when determining the cached 
object for that URL?  In other words, tell nginx to cache content for 
that location, say only 5min, and ignore all parameters when determining 
whether to cache and how to match cached content?

If I'm not explaining myself properly, please let me know and I'll try 
another route. :)

Thanks in advance,
AJ