I thinq your answer is at your fingertips. Allowing each Monk to specify their own filtration regexes could wreak havoc upon the PM server's efficiency... back-tracking in particular can be devastating. Your mission (should you choose to accept it) is to write your own filter. You're welcome to my piece of insanity if it will serve you. I wrote it for a similar purpose. I'm a pretty inexperienced Perl hacker but I like to make anything useful.
in reply to Language Filter
You can check out the code && node for PPMT && see it running here on my cheesy server. If only it could handle a cookie for my login to fully pretend to transparently be me, I'd use it exclusively. Well I hope this helps if you're still even interested in filtering content. It's good to solve the problem yourself rather than impose possibly extraordinary code && load on the host server. I'd be glad to help you in any way I can if you'd like me to. TTFN.
p.s. Initiate Nail Removal Immediately!