Need help with a rule for a test site.

I am trying to create a rule or something similar and need some help. We have 9 servers that are separated into a public pool of three servers (1 test and 2 production) for authentication two private pools (we can call them HTML and .NET with 1 test and 2 production each). We need a test environment that mimics the production environment exactly, if a user clicks a link on a production servers he goes to another production server but if he clicks a link on a test server he is connected to a another test server (when a user logs in on the test public site he is directed only to the test private servers and not the production private servers). We thought about creating new DNS names but then when a site comes into production from test it would require serious modifications, if it is modified at all then it must be put back into testing which means that it would need to be changed again and … I think you can see where this would go. Any help on this would really be appreciated. Thanks in advanced!