EDIT: I suppose I should have read the subject of your topic... Still you can do the same thing for a web filter using regular expressions filtering on message text. If you want to ONLY send those messages to web access, you can use the filter below with your "log to kiwi web access" action rule.
You can definitely filter on message text like that.
If that's not what you're looking for, please clarify your question and I will try to help.
Thanks,
Acy