interent prioritise connection

If you have three pc hooked up to the same connection can you set which pc gets priority?
A friend asked me about this and I didn't know the answer. The problem he seems to have it that 3 people are using the same connection one playing games the other uploading a huge file and when my friend just tried to do some basic surfing his connection was worse than a dialup.

You can do this sort of thing using bandwidth priorty under managed switches and routers - high end HP ProCurve or Cisco equipment...