Playing with multiple people same IP

[stanczyk08]

I know there must be a forum out there somewhere about the same topic, but I am unable to locate it atm. I am just curious on who I must contact to be allowed multiple instances of the game running on the same IP address. The only reason I ask is because my brother and I like to game together and a few times a week my friends come and game with us. They do not have a connection anywhere else but on my network so we can only play together here at my house. Any advice or ways to contacting an admin for solving this issue would be helpful.