general regexp based filter?

[Chris Quenelle]

There are two kinds of automatic messages that I get which I would prefer
to silently drop.  One looks like:

nickserv: (notice) You are already logged in as XXXUSERXXX

The other one looks like:

aolsystemmsg: You (XXXUSERXXX) are now signed into AOL(R) Instant
Messenger (TM) in 2 locations. To sign off the other location(s), reply to
this message with the number 1. Click here for more information.

I wanted to get my feet wet with Adium development, and I thought I
might try implementing a plugin is silently ignore messages
based on a set of regexps.

Any thoughts?  Already done?  Not possible?  Good plugins
to look at which are doing something similar?

--chris