Purchase Order, GRN and Invoice

Hi,

I have a situation where user wants the PO value to display the material + tax value (e.g. material A = 100, tax = 5. PO value is 105). When they do GRN, they only want to capture the material cost, which is 100.

Come invoice, user wants the PO value to be displayed = 105, and invoice will be processed as 0 tax, since tax is already added to the PO value.

Is this scenario possible in SAP?

Thanks!