Split DNS

Our ISP has a DNS entry company.com pointing to 10.4.8 server. They also have store.company.com pointing to the same server. We want to be able to take the request for store.compnay.com and redirect that request to another internal server altogether. The other server is a Windows 2003 server. We have our DNS set internally so that it works, but externally, it goes to our default website. Do I need to have ISP change their entry for store.company.com or is there something we can do here on our own server? Thanks for any help.