my $rg = Mail::Message::Head::ResentGroup->new(head => $head,
From => 'me@home.nl', To => 'You@tux.aq');
$head->addResentGroup($rg);
my $rg = $head->addResentGroup(From => 'me');
my @from = $rg->From;
my @rgs = $head->resentGroups;
$rg[2]->delete if @rgs > 2;
See SYNOPSIS in Mail::Message::Head::FieldGroup
A resent group is a set of header fields which describe one intermediate
step in the message transport. Resent groups have NOTHING to do with
user activety; there is no relation to the user's sense of creating
reply, forward, or bounce messages at all!