How to concatenate invoice numbers per payment in payment xml file

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DIF Management B.V.

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We have the requirement to send all the invoice numbers per payment to banks. we are using Disbursement Payment File Formats eText. However, there's no tag to contain the concatenated invoice numbers at payment level in standard payment xml file, but only the tag for individual invoice number at invoice level . It was confirmed by Oracle Support that it's impossible to loop/concatenate these individual invoice number in xml file to the eText format file(.rtf).