BADI or exit for WA08 to group it by allocation table and vendor

Hello Experts,

I have a requirement wherein I need to group the rows upon generation of purchase orders in tcode

WA08. I need to group them so that I can create a PDF format of the PO grouped by allocation table and vendor.

For example, If I created 4 purchase orders with allocation table 123 and vendor 456 then it should only produce

1 PDF file. Are there any BADI or exit that can group my selected rows as per my requirement?

Thank you guys and take care!