Uploading PO Headers via Excel template

When tracking vendor POs across multiple vendors/freight companies, we need to update the PO with specific information related to the whole PO, not just line items. For example, Container #, Ship Dates, Notes, Freight Company, Vessel Name, etc. We use this information for inventory planning and labor management in the warehouse. Not being able to upload to the PO Headers makes this a very manual process and time consuming.