content filtering

hi,

we are currently running two parent squids v2.1 and 10 children. each
parent is handling approximately 3500 req/minute. we would like to
include a content filtering mechanism but have been unable to find any
reasonable solution using the squids (up until now we've been doing
content filtering using the Netscape Proxy but would like to get rid of
them). has anyone had any experience in filtering content, on an TAG
basis, and if yes how has this been implemented?

thanks in advance for the feedback,

pascal.