You can Add new columns in order Grid Magento

protected function _prepareCollection()
    {
   
  $collection = Mage::getResourceModel($this->_getCollectionClass())
        ->join(
        'sales/order_item',
        '`sales/order_item`.order_id=`main_table`.entity_id',
        array(
            'skus'  => new Zend_Db_Expr('group_concat(`sales/order_item`.product_id SEPARATOR ",")'),

            'names' => new Zend_Db_Expr('group_concat(`sales/order_item`.name SEPARATOR ",")'),
            'quantities' => new Zend_Db_Expr('group_concat(`sales/order_item`.qty_ordered SEPARATOR ",")'),
            )

 );


 $collection->getSelect()->joinLeft(array('odtx1'=>'table_name'),'odtx1.product_id  = `sales/order_item`.product_id',array('odtx1.sale_name'));


 $collection->getSelect()->joinLeft(array('odtx2'=>' table_name '),'odtx2.vsaletitle  = odtx1.sale_name',array('odtx2.supplier_id'));
 $collection->getSelect()->joinLeft(array('odtx3'=>' table_name  '),'odtx3.supplier_id  = odtx2.supplier_id',array('odtx3.s_name'));



 $this->setCollection($collection);
$collection->getSelect()->group('entity_id');
return parent::_prepareCollection();
    }