FVWM: Move windows to a new desk preserving pages

Hi,

I'm trying to understand how I can move all windows from desk X to
desk Y without losing where the windows on desk X are in terms of
their pages.

I know I can do something like:

All (Desk 1) MoveToDesk 2

But all this does is take every window on desk 1 (regardless of page)
and move those windows to desk 2.

How can I essentially "mirror" the windows on desk 1 so they are in
the same position/page on desk 2?

TIA,
Ethan