Restricting key figures in BEx

Hi,

I've a reporting requirement.

The user wants to display single line item for each invoice document.

tax-1.jpg

So, I removed the Bill document number, but the problem I'm facing is the tax amount is getting summed which shouldn't happen as per requirement.

tax-3.jpg

I want to avoid summing the tax amount and display it as a single amount.The tax amount value is singular for invoice.

Can this be achieved in BEx?

This is the output I want to display

tax-2.jpg

Kindly, please let me know.