DHCP

This is the situation, AD with external DNS(Bind) internal DNS(AD integrated)which will have BIND as a forwarder. All clients will resolve via internal DNS and which is not published to out side world. DHCP Server on existing NT Server Park. Which has configured scopes (VLANs). The new AD has to use existing scopes. The Scopes setting says DNS server is BIND. If I use these scopes all the clients see BIND as DNS and that is not what I want. I do not have separate scope in existing DHCP server plus if I put new DHCP on one of the new DC than there is firewall and it won’t work either.
Any suggestions?

Shashi