batch operations on destination fields?

[eichin@kitten.gen.ma.us (Mark W. Eichin)]

I'd like to go through a gnus-summary and mark every article where the
to, cc, resent-*, or apparently-to (the "destination" fields) contain
a string, and then move them en-masse to another folder.

So far, <M-s RET #> repeated (after an initial <M-s pattern>) followed
by <B m> does the right thing. It's tedious, though, and I have a lot
of these.

gnus-summary-limit-to-author looked ideal, except it looks only at
the From field and I want to look at just about everything *else*.
Unfortunately, gnus-summary-find-matching only works on headers that
are cached in gnus-data-header as part of gnus-newsgroup-data. 

Is there a gnus function that will give me a list of articles that
match a regexp? <M P R>, via gnus-uu-find-articles-matching, looked
almost right but it doesn't actually search the headers, only the
subjects. Do I basically need to use gnus-summary-search-article (or
something stripped down from it, that doesn't do the window
manipulation) and iterate? (If so, I'll do that and post it here.)

I don't need speed per se - I'm just looking for automation...