I recommend to define different page styles. AFAIK, OOo doesn't know something like "logical page size". So, the best bet is to switch between physical page sizes using page styles. By defining the main matter margins, you can make sure that changing the page size doesn't affect page breaks.
Another option may be to manually select the printer media size in the printing dialog. But it depends on the printer driver if this works.
Finally, you may overcome OOo's limitations by creating a PDF with a certain size and resize it using PDF tools.