gnus-parameters

[reader]

I don't know if `gnus-visible-headers' is something that can even be
delt with in `gnus-parameters' but what I have below is definitely NOT
the way to do it.  Since I don't understand/know the basic principles
of elisp... I'm just monkeying around with the parens hoping to get it
right. 

The forumulation below can be evaluated without error but gnus cannot
function with that evaluated...  Basic things like opening/closing a
group are broken by it... and give errors like (wrapped for mail):

   gnus-group-fast-parameter: Wrong type argument: \
      stringp, gnus-visible-headers


 (setq gnus-parameters
       '(("[Ss]pam[0-9]*$\\|_ex$"
          (total-expire . t)
          (expiry-wait . 18))
         (gnus-visible-headers
           ("\.bk$"
            ("^X-Spam-Report:.*_FARAWAY_")))))

Can someone tell me first off if `gnus-visible-headers' is something
that can be handled in `gnus-parameters'.  

The manual talks about it and mentions that `visible' doesn't work.
So I wasn't sure if that would include `gnus-VISIBLE-headers'.

>From gnus manual:
 
     Group parameters can be set via the `gnus-parameters' variable
     too.  But some variables, such as `visible', have no effect (For
     this case see `gnus-permanently-visible-groups' as an
     alternative.). [...]

Just scanning thru various related things in the manual I couldn't
tell if `gnus-visible-headers' should work in a gnus-parameters
setting. But just going by the name of it `gnus-visible-headers' seems
like it would be considered a `gnus-parameter'

If `gnus-visible-headers' can be set for a list of groups matching a
regex in gnus-parameters maybe someone can show an example of what the
syntax would look like.

I do have `gnus-visible-headers' set globally and not sure if that
would somehow interfere. (Wrapped for mail)

(setq gnus-visible-headers 
         "^From:\\|
         ^Subject:\\|
         ^To:\\|
         ^Date:\\|
         ^Message-ID:\\|
         ^X-Spam-Status:\\|
         ^X-HP[rm].*:\\|
         ^Newsgroups:\\|
         ^Keywords:\\|
         ^Gnus-Warning:")