Components for Delphi and C++ Builder.

procedure TForm1.DBGridEh1DataGroupFooterAggregateValue(Grid: TCustomDBGridEh;
  Column: TColumnEh; GroupFooter: TGridDataGroupFooterEh;
  FooterColumnItem: TGridDataGroupFooterColumnItemEh; var AValue: Variant;
  Node: TGroupDataTreeNodeEh; var Processed: Boolean);
begin
  if (Node.Level = 1) and
     (Grid.DataSource.DataSet.FieldByName('Continent').AsString = 'South America') then
  begin
    Processed := True;
  end;
end;