Thanks Mr.Bensan for your efforts to show two approaches. I went ahead with the later approach.
Its very difficult to highlight a pie chart sector using CSS as it separates out from the shape when selected and comes in when again gets deselected.
During application load, I show all the companies value in the column graph. On selection and deselection of Pie chart values, the column graph values also changes according to the approach mentioned by you.
Thanks,
Gaurav