Purchasing Raw materials in different packaging size

Hello,

We have a scenario where we procure materials in different packaging size (25kg bag, 50 kgs etc) from different vendor.

Different packaging size has different rates. Presently while creating PO's we enter the rates manually and change the description of the material in PO.

Please suggest is there any functionality in SAP wherein we can select required packaging size and system picks up the respective price in the PO.

Waiting for a reply.

Thanks in advance.