Rewriting XML requests

I suppose this is not so much an ASP question as an IIS question.  I have an
application that we have deployed over many IIS virtual directories - each one
with a slightly different implmentation of the site.  

What I want to do is make ONE IIS application serve all of the requests.  The
requests come from different URL's, i.e. 
client1.mycompany.com/default.aspx
client2.mycompany.com/default.aspx

For example, pretent the default.aspx page reads a single XML file with the
local path of "/resources/someinfo.xml" - and I want each client to
get a DIFFERENT copy of that file.

I was close to success implmenting an HttpHandler, and mapping all .XML request
through it as an ISAPI handler, configured in IIS.  I ran into problems however
when I wanted to map different .SWF files using the same technique.

I think I'm missing something very simple here - the handler implmentation
seemed to complex.  I'm looking at IIS redirect functionality now, but it
doesn't seem to work the way I expect it to.  Whenever I turn on "a
directory below this one" the redirect stops working.

Anyone doing/done anything similar?

M@

Look into using ISAPIRewrite and parsing the different domains into query
strings you can base your serving of files on.

Jeff