Its generally not possible to combine snapshot reports after they are
created. There's a couple of solutions:
1.) Create a new blank main report and add your target reports as subreports
to that main report. Note if you do this that you have to move any data in
the original report's report header section to the page header.
2.) Output your reports as PDF files rather than snapshot files. PDFs can
be manipulated where snapshot's can't easily. If you want to automate that
process take a look at our PDF and Mail library for Access (pro or pro plus
edition) which would allow you to do it all via code.