ree Items on our website if a customer order a specific qty of one item and this information is pass

We offer Free Items on our website if a customer order a specific qty of one item and this information is passed to our F47 files, the Free item comes into our F47 files with a zero unit price, but when it goes into our F4211 file it has the base price from F4106, Is there a setting or logic that says if inbound base price equals zero, automatically bring in Base Price from F4106