Explanation on domain redirect to page using CNAME

I just need an explanation, so that I can reward this project if the explanation works: We need to redirect certain CNAME records to specific landing pages of our system. Example of what we need: Say we have a cname on a domain like: [login to view URL] We need to capture that cname1 and /landingpage1 are present in the URL, and "redirect" the request to a specific page on our system, which is in www.oursystem.com. So cname1 and landingpage1 will give us the information of what page and parameters to use for this "redirect". Obs: the address on the url shouldn´t change to www.oursystem.com. It should remain as [login to view URL] Our system is developed on classic ASP, but the functionalities of classic ASP are very similar to .NET or PHP, since they have pretty much the same functions for page redirects, etc. Ou server is a Windows Server 2012 and web server is IIS 8.0. This project will be rewarded as the explanation works. Thank you.