Revision of Multiple invoices per PDF from Fri, 2018-03-16 08:00

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. 
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