I had to look up FB2 to find out what it was!
I take it you have experience of other FB2 books which ARE structured - i.e. the format WILL do it?
Open your ePub in Sigil. IS it divided into chapters, each a seperate XHTML file? If not, it's easy to split them.
IS there a title at the beginning of each chapter, in a header style? Has the TOC been generated?
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