Restricting user's web access to specified urls

[zen_guerrilla]

Hello world,
I want to restrict a user's www access to specific url's read from a text file. What's the best way to do it ? I'm currently running a simple caching squid-2.4STABLE7 on my slack-8.1 server...
Also how could I automatically parse mozilla's bookmarks.html file and create that url-list text file i.e. w/ awk ?
I want to restrict that user's www access to url's listed on another user's bookmarks...

.:: zen ::.