Merging two pages in a single file

[tfl]

Is it possible to merge two pages that are generated by the print driver and contained in a single PDF file so that both are printed, one being rotated 180 degrees, consecutively on a single page. Each page graphic and text set is 3.375 X 2.125 inches. The pages contain both positioned text and multiple positioned graphics. The print quality must be at least 600 DPI. This process should be automated so that each print order is done the same way automatically. Thanks for any help you can provide!