Unpivot nested column groups

It's common to find Excel data sources with merged cells as column headings and nested "sub-columns". Please add built-in support for unpivoting nested column groups. An example of a work-around: https://wessexbi.wordpress.com/2014/02/27/unpivot-nested-headings-with-power-query/ The Tabealu Data Reshaper add-in for Excel can detect these column groupings automatically. https://community.tableau.com/docs/DOC-10394