How to override a DNS entry on internal network? (for soem hosts only!)

[maram66 at gmail.com]

Hello!

We have a bind DNS in our company, and we would like to be able to use
it to override the mappings provided by an external master DNS server
for our domain.

For example...

There is a ns1.mydomain.com somewhere out there on the internet and it
translates the following hostnames:

host1.mydomain.com (123.123.123.123)
host2.mydomain.com (123.123.123.124)

we now want to be able to override the entry for host1.mydomain.com if
looked up from within the company intranet which is served by the
Company intranet DNS...

BUT

... in this intranet DNS we want to edit only the hosts that we want
to override. Meaning there was no  host2.mydomain.com entry in
intranet DNS then the Internet DNS Server should be looked up and the
123.123.123.124 IP returned.

I was able to set the intranet DNS to override the whole domain but I
don't want to have to enter each Master record of the internet DNS. Is
there some way to pass the query to another domain DNS if no local
entry found?

Any other suggestions?