I want to be able to override local DNS, to resolv a specific host as a local ip instead of the public ip stored on DynDns servers.
Our current internal DNS runs under Windows 2003 Server. We have two routers with seperate internet access, one for internet access and the other one mainly for VoIp traffic. Like the image below.

We need voip.example.com to be resolved as 192.168.1.3 in the DNS server instead of the actual public ip mainly to avoid having to use the internet bandwith to browse the voip server from one of the PC's configured to use default router.