Question : AD and Primary zone DNS

I have and AD domain (mydomain.com) that spans 4 sites.
in DNS I have a zone mydomain.com (AD Integrated zone).
in DNS site1 I have a primary zone named ZoneAA and DNS site2 I have a secondary zone ZoneAA, site3 and site4 have only the the AD Integrated zone mydomain.com.
How do I make site3 and site4 computers resolve DNS requests to ZoneAA, which is not in their sites DNS servers, but it's  in Site1 and site2 Dns servers? Do I need to add forwarders? I can't think of any other work around.

In site3 all computers have the preferred DNS server pointing to the local DNS, the same thing for site4 where computers have the preferred DNS pointingt o the local DNS.

any idea?

Thanks

Answer : AD and Primary zone DNS

Site3 and Site4 need to either be setup as secondaries for ZoneAA or be configured to forward requests for ZoneAA to Site1's DNS server.

Which one is best for your situation is based on how many name resolution requests site3 and site4 do for host names in ZoneAA.  IF they do a lot, then setting them up a secondaries should make name resolution happen faster and cut down on traffic between them and site1.   If they do not do a lot of requests, then just forwarding the requests would be best.