Hi,you can use squid's delay pool feature to accomplish your task! They work like a charm provided following is true:
your squid is build with delay-pool options (squid can show this by running squid -v command on CLI) your understand very well the delay pool structure of classes & bits-bytes theory:) following links will help you alot!
http://www.visolve.com/squid/squid30/delaypools.php http://quark.humbug.org.au/publications/squid/aclsquid.html -Asim Ahmed