Since recently the dutch tax authorities allow multiple suppliers to combine their invoices in in one document.

(see article 3.2.3.1 at https://zoek.officielebekendmakingen.nl/stcrt-2017-59187.pdf)

How would you approach this in UBL? I could create one UBL document per invoice on the aggregate document, but then it's not possible to give them the same filename as the PDF.