Different DNS settings for different subnets
 

I have the following scenario

I have 100 subnets in my network and have 1 DNS server for them. I want to configure different DNS settings for 10 subnets and different for rest 90. How to achieve them.

what kinds of DNS settings? from the same server? what server? how are these subnets connecting?

here
 

These subnet srae connected by a high speed network through a router. Each subnet has 254 IP addresses. I have a single linux based DNS Server. I want to redirect the users of 10 subnets to a webpage (which is hosted on my web server) when they enter a specific URL (for example www.yahoo.com). After having a look on the page I want to give a link on my page to www.yahoo.com.