Printing seperate documents double sided?

I do prints for people and they often send me the front and back side as 2 seperate files, the printer cannot do double sided if it's from 2 seperate files, is there anyway to get around this (other than manually re-feeding the printed sheets, which results in nothing but endless paper jams if there is a lot of ink coverage on the prints)? What I really want would be to be able to take 2 PDF, JPG, whatever files and somehow get them to print as a single 2 page document. Is there any way to do this? Does windows allow you to "merge" print jobs? And what's that "print to file" option I see in most programs? Would that help?

Thanks

Print to file merely means make a file of the document.
As to how to merge 2 sep files maybe there is an option in the printer advanced settings to choose whats printed on one side and whats printed on the other side.
If the printer does that.
This may or may not help you
http://office.microsoft.com/en-us/as...646671033.aspx
http://word.mvps.org/MacWordNew/Book...ingContent.htm
Good Luck