conditional page break

Hi,

 

I am trying to find a way to conditionally start a new page within a PDF.
Basically, if block A fits on one page, even with space remaining, block B
should start on a new page. But if block A runs onto the next page, block B
should start straight after block A. 

 

I can't see a way to do this - I first looked into comparing the page
numbers, but obviously you can't do this at the XSL step of the process.
Wondered if anyone can suggest a solution?

 

Thanks,

Tamsin