I've searched high and low but I can't find any definitive answer to how to import a multi page pdf as a layer into another multi page pdf without having to do it page by page in the import as layer dialog in Acrobat Pro DC.
Say I've got a 200 page book that's going to be printed in multiple languages. I've got one pdf with my image layer, and one pdf with the copy for each language. I need to import a copy pdf as a layer into my image pdf. Both pdf files have the same number of pages, so I want page 1 of the copy pdf to be placed on page 1 of the image pdf, and so on. So doing it page by page for all languages is of course out of the question.