Game fails to launch when both players are connected to the same modem.

We have 2  PCs in the house connected to the same modem. When we join as a party and try to launch, one player will enter the game and the other one is left in the menu, When I then then try to 'Join game' off them, a lot of the time the queue just stops. Once we are able to join a game together this victory is short lasted as at the end of the game only one person loads into the next game and the other person is stuck at the same menu and has to leave and restart the joining process. We both use Ethernet cable connections if that matters.

We only have this problem trying to play with each other and it's terribly frustrating.