Reading news off of multiple news servers is great, but posting to
   foreign servers fails. What do I do?
   
   Give a prefix to the posting command. That is, type C-u C-c C-c
   instead of C-c C-c.
   
   This will be changed in the near future so that postings will go to
   the server that the group is being read from when no prefix is given.
   
   Steinar Bang <sb@metis.no> suggests a workaround until then:
   
   Put the following in ~/.emacs or ~/.gnus:
   
;; Hack for posting on foreign servers
(add-hook 'message-setup-hook
          (lambda ()
            (local-set-key "\C-c\C-c" 'message-send-and-exit-with-prefix)))

(defun message-send-and-exit-with-prefix ()
  "Call the message-send-and-exit function with a positive number argument
to make it post the message on the foreign NNTP server of a group, instead
of the default NNTP server"
  (interactive)
  (message-send-and-exit 1))