Hi all,

in the course of integration of org mode with mairix and gnus, I came
across the need for Gnus to enter a group that is recreated dynamically
by mairix -- so Gnus will need to forget everything about the group when
entering it, and read it afresh.

You can see the resulting code at

  http://article.gmane.org/gmane.emacs.orgmode/3364

the gnus-related part being