NAT problem.

I have a NAT that goes from cable to my LAN. I’m using 192.168.0.x for all my LAN IPs. I can surf the web, and even have an FTP site on one of my box. However, when playing online games, i can’t connect to the game server using both computers at the same time. I know enough about ip forwarding to have an ftp site behind the NAT, but what i would like to know is…. are there ways to connect to a game server using one ip behind the NAT from 2 computers from same LAN??? This would be similarto having muliple computers surf the net with NAT, but i need ports other than 80 to be shared by one computer. All my research has come up with blank, and would like to know if there is anything such a program or hardward….

Thanks in advance.