[xsl] Widows and orphans in XSL-FO

["Mark Wilson" <mark@xxxxxxxxxxxx>]

Hello all,
I am compiling a journal index. The output is generated via XSLT and XSL-FO. 
I have been looking for a way to deal with widows and orphans in XSL-FO, but 
all of the information I have found seems to be focused on breaks *within* 
an <fo:block>rather than *between* different<fo:block>s. My problem is that 
I only want to end a page if the processor has started rendering (or has 
completed rendering), a specific <fo:block>, one containing the content from 
an <Article> element.  Is there a mechanism for forcing a page to end with, 
or within, a specific <fo:block>type?

The index itself may be seen at 
http://www.knihtisk.org/library/specialist/index.htm.

Thanks,
Mark

Pictures explain better than words. As you might imagine, the actual XSL-FO 
style sheet is quite complex. Thus, rather than supplying the style sheet 
itself, the seven possible problem configurations are shown below. Each of 
the five elements is rendered in its own <fo:block>:

<Heading> page 1
<Article> page 2

<Heading> page 1
<SubDiv1> page 2

<Heading> page 1
<SubDiv1> page 1
<Article>    page 2

<Heading> page 1
<SubDiv1> page 1
<SubDiv2> page 2

<Heading> page 1
<SubDiv1> page 1
<SubDiv2> page 1
<Article>    page 2

<Heading> page 1
<SubDiv1> page 1
<SubDiv2> page 1
<SubDiv3> Page 2

<Heading> page 1
<SubDiv1> page 1
<SubDiv2> page 1
<SubDiv3> page 1
<Article>    page 2