I would like to know if it is possible to do a port forward with a IPTable firewall as I will describe:

1. A call to the "local" web server. (on the internal lan: is called from the outside by http://anydomain.any/catalog_name.

2. The router where the IPTable script is located is

3. Can a rule be constructed as something like:
iptables -t nat -A PREROUTING -i ppp0 -p tcp --dport catalog_name:80 -j DNAT --to-dest

Why? I would like to reduce the number of open ports but still have a numeber of machines with different apps on them and I would like the site to be seen as one and not several (ie one port and one domain)