(docbook-xsl/FO) only use space-before if 2 sects follow each other directly

hi,

if i got a xml like this:

(...)
<section>
	<title>...</title>
		<section>
			<title>...</title>
(...)

the space between the two titles is space.before of the 2nd section.
is there a workable way to use soace.after of the 1st section instead?


thx,
	Sebastian