Authority check at field level in the sales order

Dear all, our business requirement is the following:

only some users should be able to see the prices (including netwr, netpr,...) in the sales order depending on the authority check performed on the sales group field.

This means that for an order of sales group 'A':

a user of sales group 'A' can see the prices and change the order, a user of sales group 'B' cannnot see the prices but can change the order, a user of sales group 'C' can display the order but cannnot see the prices.

I ask you if such a scenario can be realized in SAP.

We currently run SAP ECC 5.0.

thx all !

bye Roberto