DNS forwarding
 

can anyone help me on how to establish static routes between the domains so that each domain could communicate with one other and how to create DNS forwarders for each named server to provide inter-domain name resolution.

Try using Simple DNS to help you out.When Simple DNS Plus receives DNS request for a domain name configured for forwarding (Options dialog - DNS - Forwarding), it skips the normal DNS resolution process and instead forwards the DNS request to the specified DNS servers asking them to do the resolution work for it.
You can configure Simple DNS Plus to use forwarding for all domain names, and/or for specific domains (including their sub-names), and use extended forwarding: