Multiple suppliers invoicing on one document

Hello,

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)

Am I correct this currently is not a possibility using UBL?

It could easily be achieved by allowing multiple elements (e.g. <Invoice>  to be combined in one root element, for example <InvoiceCollective>.

I like your thoughts on how to solve this.

Best,

Jeroen