Hiding duplicates marked with "M"?

Hiding duplicates marked with "M"?

[Lloyd Zusman]

[ This is an auto-generated, courtesy copy of a message that I've
  also posted to the gnu.emacs.gnus newsgroup. ]

I'm using pgnus-0.59 under XEmacs 21.2-beta4.

I'm now using a lot of `nnvirtual' groups, which sometimes contain
duplicate articles that come from the various component newsgroups.
When I have entered an `nnvirtual' group, read all the articles, and
then return later, sometimes an article has arrived which is a
duplicate of one I have read earlier.  In this case, I see the article
in the summary buffer, marked with an "M".

I would like to hide these articles completely.  

The variable `gnus-suppress-duplicates' is properly set in my
configuration, and I have tried playing with
`gnus-summary-ignore-duplicates', but this setting doesn't seem to
affect the presence of these articles marked with "M".

Any ideas?

Thanks in advance.

-- 
 Lloyd Zusman
 ljz@asfast.com