2 pages on 1 ?

[PMA]

Hi List.

I have a LilyPond score printing to 11X17 paper in landscape mode.
Most of the result -- with staves stretching fully across the page of
course -- is looking okay.

But one movement isn't.   It's measures, nearly a half-page wide,
would to my eye be most readable if they were arranged in two
columns (to be read bar-to-bar *downwards* rather than across)
with the columns separated by ca an inch of empty space and a
top-to-bottom-of-page vertical line in the middle.

Before pursuing ugly attempts to fool LilyPond into "allowing" this,
I may as well ask -- Is there a straightforward way?  Can you tell
LilyPond: "The physical paper is 11x17, but just pretend that the
"pages" you're printing are 11x8, and then print them two at a
time side-by-side with this space & big vertical line in between"?

(Or had I better just force an inch of empty mid-page staff, make
that staff portion transparent, force whatever clef to print after it,
and then later -- via a PDF editor -- cram in the vertical divider?)

Thanks in advance for any suggestions!

Pete