How to best create multiple two sided pdfs with the same back page

[30170124lx3u]

I was having an issue recently finalizing a project. The end deliverable was to be a two-sided postcard, with multiple versions of a front cover to be run with a data merge in Indesign, but using the same backside for all. After the data merge was finished the document contained 548 front pages. After extracting the pages in Acrobat I had all single pdf files of the front side. I was wondering if anyone had a suggestion for the most efficient way of combining the individual front sides with the back page document. I was hoping there was a quicker way than Combining Multiple PDFs and having to manually click both documents 548 times. 

Thanks in advance for any suggestions!

[Abambo]

Why not doing in InDesign a 2-page document, with the first page the mail merge data and the second page being the common back page? You run mail merge, and the resulting PDF can be split into documents of 2 pages each.

[try67]

I didn't understand if these are individual files, or one single file.

If the former, you can use the Action Wizard to insert a file to the existing document, and run it on all of them.

If the latter, you can use a script, like this (paid-for) tool I've developed that does just that:

https://www.try67.com/tool/acrobat-insert-one-pdf-file-into-another-multiple-times