Another wildcard question for virtual hosting from a bind newbie

I am running Redhat 8.0 and trying to use bind to solve my servers dns
issues?
I have been searching the internet but I cant seem to get any of the
solutions to work.

Deadpan110 tries to explain the problem:

My webserver is called mydomain.com and is inside the network on the
orange
IP address of 192.168.1.2
If i log in to the shell on that machine and type:
host mydomain.com
i get
ind-web.com has address 192.168.XX.XX
but the server can have unlimited virtual hosts (apache 2.x.x)...
so if i type
host someusername.mydomain.com
i get
someusername.mydomain.com is an alias for mydomain.com.
mydomain.com has address XX.XX.XX.XX (external IP of a smoothwall box)

So the question is this:

how do i get the server to know that someusername.mydomain.com is at
192.168.XX.XX (or localhost) and not XX.XX.XX.XX (external address of
a smoothwall box)?

I have found information about using wildcards with bind but I cant
seem to
get anything working (Im not quite sure what to add to named.conf
either but
I do know how to stop and start the service).

I could always add EVERY virtual host to /etc/hosts and restart the
service
that uses the hosts file and continue to do this for every virtual
host added, but that defeats the object.

I know this subject has been covered a lot in the past, but if anyone
can help, i will be greatful!!!

Deadpan110