We are offering multiple SSL-enabled services in our local network.
To avoid certificate-warnings we bought certificates for server.ourdomain.tld and firewall.ourdomain.tld.

We now created a zone in our local DNS-server in which we pointed the hosts to the corresponding private-ips.

Now, each time another record for ourdomain.tld, like for example www.ourdomain.tld or alike are changed, we need to update it on both our public-dns-server AND the local dns-server.

I would like our local bind-dns to serve all the information from our public-dns but serve different information for these 2 hosts.

I know I could possibly have our private-ips in our public-dns but I don't want that for security reasons.

The internet dns-server is being managed by a third party, while we have full control of the intranet one. Because of this I am looking for a solution which lets the intranet retrieve the records from the internet one.