I need to show comma separated by array values for column ‘category’ in grid. When we try to group category column, instead of just grouping with comma separated values, need to display unique category followed by respective category data under it.

I need to show comma separated by array values for column ‘category’ in grid. When we try to group category column, instead of just grouping with comma separated values, need to display unique category followed by respective category data under it.