You can try Split DNS
Split DNS Names
Split DNS lets an internal DNS server resolve a list of centrally-defined Local Domain Names, while ISP-assigned DNS servers resolve all other DNS requests. It is used in split-tunneling connections;
the internal DNS server resolves the domain names for traffic through the tunnel, and the ISP-assigned DNS servers resolve DNS requests that travel in the clear to the Internet.
Enter each domain name to be resolved by the internal server. Use commas but no spaces to separate the names.
