Sorry, we must not be communicating. I'm having a hard time understanding what you wrote.
Something about a file... Is your other rule in a file? How does squid find your other rule that is blocking these sites? Where ever it is, just before that add the ACL I suggested. It has to be before and not on the same line, see:
http://wiki.squid-cache.org/SquidFaq...2BAC8-Or_logic
If you are now asking "how do I include external files into squid, that's a horse of a different color. Search the documentation and wiki for that answer.