You can set up the spreadsheet to give users the ability to form a range of expandable and collapsible rows or columns. This is useful for handling rows or columns of data that do not need to be visible all the time but are related to adjacent rows or columns. This is sometimes referred to as range grouping or Excel-like grouping or outlines.
For more information about grouping see, Managing Outlines (Range Groups) of Rows and Columns.