Sorry Aurora, but I think that's wrong.
Apache virtual hosting will let you have multiple hosts pointed to the same IP and will serve different websites according to the hostname specified in the http request.
e.g.:
In example.com zone file:
www.example.com IN A 192.168.0.4
xyz.example.com IN A 192.168.0.4
In anything.com zone file:
www.anything.com IN A 192.168.0.4
xyz.anything.com IN A 192.168.0.4
Virtual hosting will allow you to server between 1 and 4 different sites for each of these hostnames. However you still need to have different zone files for each domain.
AS such, it doesn't answer John's question as to whether it's possible to have a single zone file where
www.* and xyz.* (using * as a wildcard here) will work. The answer is that it won't. There's no such thing as a universal zone file.
Carl.