You can restrict a customer to specific ship-via codes if that customer does not accept shipments from certain carriers.
If a particular ship-via code is to ONLY be available to specific customers then the ship-via codes record must be flagged as indicated in the following screen shot, otherwise you can skip this step. Field 37 of the “SH” (ship-via) codes record says “Restrict by SH_CUST”. Flag the appropriate ship-via codes record with a “Yes” in this field.
Once you flagged all of the ship-via codes records that should be restricted (remember – ONLY the ship-via codes that are to be available to specific customers required the previous step) then create a “GS” (general string) codes record similar to the one in the following screen shot that defines the customer and that customers legitimate ship-via codes separated by commas.
In the example, customer 100747 only accepts shipments by ship methods represented by codes 15 and 17.