Bleed tabs - automation?

[Steve Rickaby]

Sarah O'Keefe and Sheila Loring's excellent FrameMaker 7 'complete reference' book gives a method for setting up bleed tabs (thumbtabs) that requires manual deletion of unnecessary tabs (i.e. all but the current chapter) in production edit. Within structured FrameMaker, is there a way of automating this? 

What is needed is a means of rendering objects visible/invisible depending on their chapter number. Perhaps some way of making conditional tags sensitive to their context in the book...?

Another approach I've tried is to include a rotated B flow flush to the page edge and insert the bleed tabs as conditionalised anchored frames. This allows tabs to be turned on and off with conditions,  but I don't like these objects being on body pages, and it doesn't get round the issue of making them sensitive to chapter number.

Failing that, I guess it could be done using the feature for mapping master pages to paragraphs, but I cannot see it working out very elegantly, as one would have to hack some sort of 'hidden' mapping between chapter number and paragraph tags.
 
Any ideas, anyone?
-- 
Steve