While using NoticeDocumentReference to refer to a PIN, it should also be possible to refer to specific lots (eForms: Previous Planning Part Identifier - BT-1251)

Allowing repeatable use of ProjectProcurementLotReference in NoticeDocumentReference would do.

<cac:NoticeDocumentReference>

    <cbc:ID>For (BT-125) Previous PIN identifier</cbc:ID>

    <cac:ProcurementProjectLotReference>

            <cbc:ID>1</cbc:ID>

    </cac:ProcurementProjectLotReference>

    <cac:ProcurementProjectLotReference>

            <cbc:ID>2</cbc:ID>

    </cac:ProcurementProjectLotReference>

</cac:NoticeDocumentReference>