59229 Redirect Script w/db lookup

This is a simple project for someone with the right skills. I am looking for a script that will review the reffering link on all new site visitors and if it finds certain elements (city/state or zipcode) in the details of the referring URL then do a dabase lookup (if city/state and no zipcode) and immediately direct the user to the appropriate landing page. The keys to look for upon a user requesting the home page is city AND state OR zipcode. About 50% of our hits include this information, the other 50% would just go to the standard home page. If the script finds city AND state informatiAND NO ZIPCODE it would need to peform a database lookup and find one zipcode for that city (there will be many, just using the first if finds in the database) and bring up the page with the corresponding name, for example entry url includes T=Houston&S=TX then the page to display after looking up and finding zipcode 77070 for Houston, TX is \zipcode\[login to view URL] If the zip IS included in the in the details of the referring URL then simply direct them to \zipcode\[login to view URL] where xxxxx is the zipcode.