Michael, as see you'd like to have a fine-tuned control about what  is "next" and "prev". This can be accomplished by "html comment bot directives" I mentioned  before. Would you like to work with me to have a try with "my temptative, bot-oriented  approach" to the problem? In my experience, this is best obtained working on a real case. So, if you are so bold to have a try, and you have one new work (t.i. a new book where chapters/sections hasn't be created) to use as a real test into en.source, tell me! I like exploring, and I've just registered a bot into en.source, that is waiting for some work to show what it can do...  I can't promise you any result but some headache, but it could turn out an interesting adventure.

Feel free to use my personal mail or my user talk page into en.source or into it.source,if you like the idea.

Alex_brollo