4 Pack Ordering

Hey I was looking to pick up additional copies of The Political Machine 2012 after the reception received from www.steamgifts.com from a couple giveaways,  however Stardock only offers single copies through their distribution method so; is steam the only way possible to order 4-pack, and is there any chance in coupons for people who already own the game who wish to continue supporting, I'm looking to set my brother up with this game for some multiplayer competition so would we be able to play each other online or locally with the same copy or will he have to have his own copy in order for steam to allow him to play