Kicked from game (3 trying to play on the network)

[kamak86 1]

Recently my friends and I tried to all join a server on the same network.

1 pc can join the others no matter what.

the other 2 pcs can join #1 but cannot join each other.

PCs 2 and 3 cannot join each other in any server, but can join other servers. We tried moving Ports from the switch to the router to directly into the modem (TMC 4 port modem).

When ever they try and join each other the person who is the latter to join gets a "Kicked off game" message.

PLEASE HELP!

Kamak86