Cache Only Dns Entries?

I have a Windows 2003 cache only DNS server on my internal network. I have forwarders setup to point to the OPENDNS servers to resolve external IP to hostname resolutions.

My issue is that I have an internal website that I need about 50 users to have access to. I need them to be able to access the site by hostname and not by IP so I need internal resolution.(I have tested it and I am able to access the site via IP:Port number but cannot when I input the hostname)

Question: Can I input a hostname entry on a ‘cache only dns’ server for resolution or do I have to configure zones on that dns server?(adding zones would defeat the purpose of having a ‘cache only dns server’ right?)

Thanks for any direction.
-R