Dynamic reorganization of mail groups

[victor@algebraic.org (Victor S. Miller)]

I would like to dynamically reorganize my mail groups using a "move to
front" method:

When I group receives new mail (via some split), it is moved to the
top of the list of mail groups.  Is there a hook that gets invoked
when a split files mail in a group?  Has anybody else written code to
do something like this?  A less crude alternative to this is to have
score associated with each mail group, which is increased when it
receives new mail, and then sort the groups according to score.

Victor