How to group data in Chart?

[sallyGals]

i had create chart in the system, the chart fields are target, current stock, stock minimum, and stock maximum.Now i want to show the chart which is group by target, means the highest target will display first then follow by the lowest target...
But i have no idea to do it, can anyone tell me how to do?
thx.

 

[sallyGals]

i had solve this problem already. By the way, i have another problem now. I have 30 product in Y axis, I want to categorize 1O product then put a mark there in the axis there, so it will make user easy to count the total of the product.How to make it?
thanks for helping.