Can I create DNS records for some hosts, delegate other queries in the same domain to another DNS server?
Delete your "bar.com" zone from your W2K3 DNS server. Create a zone "gum.bar.com", and create a blank host record in that zone pointing to the LAN IP of the local server. Problem solved. >smile<
The W2K3 DNS server can't be simultaneously authoritative for a domain while forwarding queries that it can't resolve to another DNS server. It's just a limitation of the product. Working around it, per the above, is how we've always handled it.