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Why can't you use two separate DNS servers on a domain and update the A Record with where they should go?
ns1.domain1.com
ns2.domain1.com
ns1.domain2.com
ns2.domain2.com
The goal is to allow the sub-domains to use the domain2.com DNS and the /public_html/ or mydoaim.com to use the DNS servers from domain1.com.
Some hosts/registrars allow you to create NS records. You could then create a record like this:
subdomain.domain.tld NS ns3.domain.tld
This will delegate the request for the lookup to another nameserver. Naturally, passing that request will require contacting the nameservers of the primary domain, which is probably not something you want.
To be honest I couldn't think of a reason why you would want this; you might want to consider registering another domain.