Any way to find what URL patterns I match? (I == Servlet)

I have an application where one servlet will respond to a request with a URL targeted to another servlet. Something like:

Client to Servlet 1:
  Can I get a new phone?
Servlet 1: 
  Sure; here's what you need to ask for (http://blah/phone/1234/)
Client to Servlet 2:
  Can I get 1234?
Servlet 2:
  Sure, here it is...

To do this it would be nice to either:

• have servlet 1 discover to what URL pattern(s) servlet 2 will respond
• have servlet 2 publish valid a URL pattern for outsiders creating URLs targeting it

Both of these require some sort of introspection on the servlet configuration, preferably at init(). But the URL pattern part of it just isn't there -- I can get my servlet name from the ServletConfig passed into init(), but I can't take that name and get additional information from the ServletContext. Am I missing something?

(I know that I could just declare the URL as an initialization parameter to either servlet 1 or 2, but then I'm declaring it twice. I also know that I could pull that parameter out into a configuration file and do some pre-processing of web.xml before deployment, but down that path is madness.)