Can I limit bandwidth using winpkfltr for each ip/source combination?
Yes
If so, Please give me some directions on how to do this?
The basic idea is pretty simple. One possible realization is the following. Create a queue and put all packets into. Also create a periodic timer and each time when timer fires calculate time passed since last timer. Then claculate the amount of data you can allow to pass for the given time and process as many packets from the queue as it fits into clculated amount of data.