How do I merge and combine PDFs into one single file after checkout?

[hptree]

Hello all,

I would like to know if anyone has every been able to combine/merge multiple digital products (PDFs) into one single downloadable file? My plan was to allow the customer to add multiple single page PDFs to cart as separate entities and then be able to download one single file that combines all into one large PDF. 

Currently after checkout, each digital product gets a sperate download link and the customer is then forced to combined the PDF files and print all separately. I would like to save the customer the hassle and be able to download and print one single file.

So far I have tried 3 apps but they are unable to perform this task. Does any have experience with this?

Thank you! Any feedback is much appreciated.