are you allowed to configure dns entries at one or both of the dns servers of you ISP?
I assume you are not.
Therefore, the only way, to manage that, is to run your own dns server in house.
This dns server should use your ISPs dns server in the forwarding section.
But you can add your own entries, like RRs (Resource Records) and PTRs (Pointer Records) to your dns, to point to you local apache server.
Then all clients should use you inhouse dns server, to resolve dns queries.