You may want to google with some keywords like traffic shaping or hierarchical token bucket. You should be able to find a Howto, how to set up a router, helping to solve your problem by restricting stream-usage for some Programs, etc.
-- Hi, I am a Signature Virus, Copy me into your ~/.signature to help me spread! -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]