subdomains without a parent?

[Dave Wreski]

Hi all.  I'm using 8.2.2p5 and have nameserver ns.a.domain.com and
ns.b.domain.com.  I'd like to be able to resolve hosts from one domain in
another and vice-versa.  Can this be done without creating a nameserver at
ns.domain.com as a parent and delegating down to the ns.a.domain.com and
ns.b.domain.com servers?

Thanks,
Dave Wreski