Grouping data on Pivot Table

Hey everyone,

I have enclosed the sample data for understanding. I have data which much more complicated than the sample data, but the working principle would be the same. When I am implement a pivot on the data, I want it to display the top two or three items, and group the rest as "OTHERS" as one group. Additionally, I want one group to be displayed (say J from the sample data to be displayed everytime, irrespective if it falls in the top three.

Please note that I need to do this without using macros or formulas. Running macros is impossible on the user's computer, and as I mentioned before, the data is too complicated and the user can choose any view from the pivot he or she wants. Too many formulas would complicate the file and make the file heavy which won't be good and reduce the flexibility.