private function DeleteOldMemberGroups(array $selectedIDs)
    {
        $sql = Access::SqlBuilder();
        $tblPgGrp = PageMembergroup::Schema()->Table();
        $where = $sql->Equals($tblPgGrp->Field('Page'), $sql->Value($this->page->GetID()));
        if (count($selectedIDs))
        {
            $inSelected = $sql->InListFromValues($selectedIDs);
            $where = $where->And_($sql->NotIn($tblPgGrp->Field('MemberGroup'), $inSelected));
        }
        PageMembergroup::Schema()->Delete($where);
    }