Answer to your first question is that the ZPA segment does not repeat at the segment or field level.
Second question: For every field populated in the ZPA there would need to be a corresponding OBX segment at the end of the ORM message. They would need to be sequentially numbered and the field # in the ZPA would need to be the variable data element identifier in the OBX.
If this helps, the new HIS system being installed is McKesson’s Paragon going to a 3rd party lab system, Cerner Millenium.