Variable Depth Section Tabs in region-end

I've successfully configured a fairly complex set of pages for the production of a technical manual with XSL:FO.  I am having difficulty with section tabs -- reverse copy blocks that appear on the right-hand side of odd pages. While I can produce the section tabs, using retrieve-marker in the region-end, I'm unable to vary the depth at which these tabs appear, based on the section number.

Things I've tried:

Using xsl:choose within xsl:attribute in the static-content block
Using xsl:choose to determine the xsl:attribute in the static-content block
And myriad other "hacks."

Can someone point me in the proper direction for resolving this issue?

Much appreciated.

Bryan Burnett


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