Show in a pivot a range of results coming from expressions

[canmarroig]

I've in a report an expression that calculates my sales margins and i want to create a pivot table to show in columns different range of margins:

<- 100%

from -100% to -50%

from -50% - to 0

from 0% to 20%

and so on......

and i can't touch the table in excel i use to generate report.

Can you help me please? Thank you