chunking at book level

Hi all !

For my documentation, I have a set of many books, is it possible to
make the chunk output splitting at book level to have only one page per
book, instead of splitting at chapter level ?

I've tried to decrease the chunk.section.depth to 1 or 0 but it has no
effect.

Maybe can I do this by customizing a template in the xsl stylesheet but
I don't find which one, could you help me on that point ?

thanks in advance !

Marie.