How can i match a dynamically changing url in VCR

In my Ruby on Rails application there are 2 Localhost servers running. I am writing test cases for the 1st server and so I have to mock the 2nd server. For this I am using VCR to record the responses I get from the 2nd server and play the recorded cassette while running the tests on the 1st server.

I am stuck at the part where the 1st server makes a request to 2nd server(the session_id in the URL changes each time) and I want the response to be same every time it makes a request.