I'm not sure that I understand exactly what it is that you are doing so I'll assume the following:
Code:
A. All machines on your network use a netmask of 255.255.255.0
B. You are using 2 separate networks 192.168.2.0 and 192.168.3.0
C. Your ClarkConnect server is set to act as a gateway between the two networks as listed above.
The reason all of your existing computers see everything regardless of what the gateway is set to is because they are on the same LAN. For example, if you have machines using both 192.168.2.X and 192.168.3.X IPs that can see each other, then the netmask on those is likely set to 255.255.0.0 and not 255.255.255.0
Otherwise, you'll have to have an appropriate gateway that will route traffic between the two LANs.