I have a line .kml which is needed to converted to shape. And I need to make a relation between "Folder" and "Placemark". I have a common field (kml_id in "Folder" and kml_parent in Placemark). How can I join them ?

I have a line .kml which is needed to converted to shape. And I need to make a relation between "Folder" and "Placemark". I have a common field (kml_id in "Folder" and kml_parent in Placemark). How can I join them ?
