Pie chart has an option to display top n slices and group rest of the slices to a single slice called 'Others' . While we click on that 'Others', it will show all items within that Slice. But we don't have this option in Bar/Column chart. Here is a script to group top n bars in Column/Bar chart.
Create a Bar/Column chart
Add below script to the widget and specify how many bars need to be displayed. Rest of the bars will group to single bar called 'Others'
Save the script and refresh the widget
Contact us for the script
Value of bar 'Others' is the SUM of values of items associated with the bar.
This functionality works when dimension in X-axis has no filter. For example, if X-axis shows 'Region', the functionality works well if all regions are selected in dashboard filter. If only few Regions are excluded or included, chart will show all bars.
Contact us if you need to customize the existing behavior of script.