Hiding columns by which the records are grouped
You can configure the view settings so that when you group the records by a column, this column is automatically hidden in the grid (the heading of this column is shown in the Group Panel).
To enable automatic hiding of columns by which the records are grouped:
Right-click anywhere in the grid and choose Customize View from the pop-up menu.
In the Customize View window, click the Options tab.
Under Grouping, select the Hide Columns on Grouping check box.