Point me in the right direction please....sendmail to MS exchange BIND config

[CliveH at lana.pathlink.com]

Our current environment consists of a HPUX unix server and a Windows
NT Server. I want to 'sendmail' from unix server to NT server, so BIND
must have to locate the domain to make mail delivery possible(?).
Exchange is up and running on the NT server with a valid DNS
configuration. In setting up BIND on unix, should I attempt to set up
the resolver to query my windows NT DNS name server, or treat the unix
as a discrete entity and configure BIND as a root name server.

If I could get over this conceptual hurdle, maybe the rest will slot
into place..?

Any advice would be appreciated