Having a little more documentation on what all of these hooks are and
what you can do from where would be useful, too.
gnus-summary-mark-article just doesn't work from
gnus-select-group-hook (invoking duplicate suppression fails because
gnus-data hasn't been built), but modifying the gnus-newsgroup-* lists
directly is tricky.

> I should probably use gnus-newsgroup-unseen rather than
> gnus-newsgroup-articles.  But for a first pass, this appears to at
> least be close.

-- 
David Maze             dmaze@mit.edu          http://www.mit.edu/~dmaze/
"Theoretical politics is interesting.  Politicking should be illegal."
	-- Abra Mitchell