[mod_python] Co-ordinating ccess to a single-use resource

Hello to everyone.

I am responsible for a project using Apache 2.0 with mod_python in a 
Win2k environment, the choice of OS being dictated by the fact that the 
purpose of the server is to supply access to a proprietary, supplier 
written Windows program to our user base via the web.

That program is single threaded and provides for only 1 user at a time. 
Access to the program in Python is through  win32com.

I am using a mod_python.publisher handler.

All the http requests come through a single proxy server with a static 
address but not all are from browser clients. Some are originating from 
perl programs but all requests are directed to a single request handler.

Can anyone suggest a method to control access to this single user 
resource. In a non-web programming environment, I'd just use a mutex 
semaphore to co-ordinate access among the threads but I am too much of 
newbie with mod_python and Apache to implement a workable solution so far.

What mechanism can I use to create a shared resource that I can lock and 
have other requests wait until the resource is unlocked?

Thanks.