Cross-references to heading and page number together

Where a cross-reference to a heading and a page number are listed together, mark both together in an xrefGrp with the heading in an xref element and the page number in a pageNum element.

This will allow one link for the entire cross reference, where the ref attribute points to the div[1-7,N] element with that same heading.

Introduction to Legal Systems and Practice, p. 14


      <xrefGrp>
             <xref ref="he-9780199231690-chapter-1-div2-1">Introduction to Legal Systems and
          Practice</xref>, p. <pageNum pageId="14">
                 <xref ref="he-9780199231690-chapter-1-milestone-14">14</xref>
             </pageNum>
         </xrefGrp>