DNS in subdomains

I am trying to set up DNS on my Windows NT/2000 network. I have created a zone (abc.com) and 2 subdomains (test1.abc.com and test2.abc.com). The problem I have is outlined below:
I have a W2K PC set up with test1.abc.com as its DNS suffix, when I try to ping a server which is under the test2.abc.com subdomain I do not get a response.
How should I set up the DNS server to allow clients in either domain to resolve names that are on the other subdomain.