I would recommend you have a squint at DSCP marking your traffic and then policing based on the markings or something.
Windows 7 has the ability to mark traffic by itself (I used to slap DSCP46 / Expedited Forwarding / Voice) on my gaming traffic so I imagine all operating systems have the ability in some form.
Next, you'll need a router or L3 switch capable of examing the DSCP markings. I'm no expert but typically, one define a 'Priority Queue' that has absolute highest priority but very little actual bandwidth assigned to it. Tiny UDP packets, typically, voice, gaming traffic, etc.
Then, you have another 3~ queues for 'other' stuff at varying levels of priority. Cisco does all this quite easily but I bet there's loads of ways to achieve it.
Cisco has terms like 'WTD' or weighted tail drop, 'SRR' or Shared Round Robin.
Hope some of this helps