[pdftex] Strategies to embed existing pdf documents into tex source file, but not as a graphic?

[W. Craig Carter]

I am wondering if the followin is possible:

I'd like to embed an existing "file.pdf" into 
my "source.tex"  The existing pdf file may be 
several pages long with page settings that 
are smaller than source.tex's.  Ideally, the 
resulting pdf would have a little sub-window 
with scrollbar and the bookmarks of file.pdf 
would be available to source.pdf. 
i.e., something that emulates 
\includegraphics specifically for pdf 
documents:
  \includesubpdf[width=6in,height=3in]{file.pdf}

W. Craig Carter