Wifi sharing

hey guys, im trying to limit the wifi bandwidth to the 5 other neighbors around my house. I have a Rosewill RNX-N4 router which i bought to use for the wifi sharing. I also bought 3 8dBi antennas for it, mounted the router up on the roof and all 5 of them are getting around a 60-80% signal, so none of them get Disconnected. Im on a 6Mbit line but plan on upgrading to the 12Mbit line soon. My problem is that some of them are hoggin the bandwidth and slowing everyone down to dial-up speeds.
I already have the QoS setup on the router but even then it slows some of us down. I have Bandwidth Control Enterprise installed on the server that the router Rosewill is connected to but the program only limits the network connection, not the user.
Does anyone know of a program that limits the Users connected ? and not the just network connection line ?