Metadata for sort order
If source data contains a sort order element capture it in a metaDescribes element with attribute predicate="sortTitle" within the metadata at root element level, chapter, e, and document level.
//metaDescribes[@predicate = "sortTitle"]
<metaItem about="e">
<metaDescribes predicate="sortTitle">JOHNSON, HUGH ERIC ALLAN</metaDescribes>
</metaItem>