All versions of FlexGrid support content-driven cell merging.
To enable cell merging, set the allowMerging property to indicate what part or parts of the grid you want to merge, and set the allowMerging property on specific row and column objects to true. Once you do that, the grid automatically merges cells that have the same content, grouping the data visually.
In the example below, the allowMerging property is set to true on the Country, Product, Color, and Active columns.
Try changing the value of the grid's allowMerging property and sorting the merged columns to see merging in action.