Make Server authoritative for sub-domain only

Hi -

Is it possible to configure Server to be authoritative for a sub-domain only?

My usage is that i run Server to host basic services, using dyndns to provide resolution from a dynamic ip.

Therefore i have a split-horizon DNS setup with a primary zone of 'dyndns.org', and an A record to resolve to the machine running Server.

However, if i ever need to visit another sub-domain of 'dyndns.org' i have to create A records for each and every other request i may have (members.dyndns.org for example).

I suppose another way of saying this would be - is there a way to pass requests to '*.dyndns.org' onto the forwarding DNS servers, except for 'myserver.dyndns.org' which would resolve internally.

Many thanks