Related: Watch the video clip on how to group and ungroup data in a pivot table
The grouping can be done on text, dates or numbers with each type offering different options. Dates can be grouped into days, months, years, quarters and it even allows for grouping of time. Numbers allows for groups based on the intervals you want. For the text grouping you simply need to choose the items you want grouped together.
In order to do this it is as simple as right clicking on one of the cells and clicking the UNGROUP option.