Updating one price list from another one

Dear all,

I need to update the price list A copying the values of the price list B only for the items of a specific item-group.

How can do it using the SAP B1 client?

I try using the Price List form (Updating with price list selection option) but I have an error message:

Unable to update basic price list or rounding method for selection criteria item Message 3506-11

I don't want to use the Special prices form.

Can someone help me please?

Best regards

Emanuele