Total of Top N in Bar Chart

[#1]

Dear Folks,

I have requirement where in need to show a bar graph, with

1. top 10 products,
2. then sum of all top 10 products in single bar
3. lastly show total of all products in single bar.

I am able to achieve point 1 and 3 but not 2nd, please find the screen shot of my chart.

Is it possible to achieve it in charts expression or i have to create ranks in scripts and then use them in my set analysis.

Regards,

Vasim