Implement Server to Server Tracking/Third Party Tracking

Hi, We run a site where we do a lot of affiliate marketing and are currently promoting offers from five networks on our site. We are looking for someone who we can consult; and can help us integrate impression pixel OR server to server tracking so that we are able to successfully track conversions. Since the offers are dynamic in the sense that they keep changing and we are constantly putting up new ones on our site - We are looking for a one time implementation for each network. We are open to Server Side Implementation, Google Analytics (if it possible to do this there) or other third party tools/services that can do this. We will first test, a small project, with a Freelancer; and only then move forward with full implementation. Thanks,