How to play on 2 machines behind a router at the same time

[Gecko]

Ok, I have a slightly complicated issue here and I'm a bit lost on how to make it work correctly if it will work at all.

First, I have a couple of boxes setup in my office that are connected to a SOHOWare BroadGuard Router. The router is connected on the WAN side to the ethernet connection provided in my office by my landlord. This connection is connected to a switch and router that are then connected to a T1 line.

The landlord's tech has assigned one private IP address to me and it is on my router. I then have the router assigning IPs to my boxes via DHCP.

The problem I have is this........one box can connect to NovaWorld and play with no problem. As soon as we attempt to connect with the other box, the first one gets kicked off (CI.)

Anybody have any thoughts or suggestions? I'm assuming it's an issue of trying to connect via the same IP address. Any way to get around this?