Hidden groups

I very much want to switch from phpBB to PunBB, but I am missing one
feature, which is vital to us.

That is the one that lets the administrator hide certain forums
completely.

That would mean that in the "Forums" andministration panel, under "Edit
group permissions for this forum", along with reading and posting
permissions, we would need a setting that controls if a forum is visible
to a particular group.

As an explanation, that function is important to is because we are
organising a LARP, and need to have forums for groups which are not to
be known to the other players, to avoid spoilers.