A company sells to a customer with multiple delivery addresses. The customer has different carrier accounts for each of their delivery addresses.
With Small Parcel Shipping enabled, one can specify carrier account numbers by carrier. Only one account per carrier is permitted.
The idea is to provide a UX consistent with the "All/Group/Table" found elsewhere in the application. For this idea, only "All" and "Table" would be needed. The "table" selection would allow the selection of one of the address records on the customer. When processing parcel shipments, the customer/carrier/address would use the address specific carrier account information or "fall through" to the "all" condition.
Long term stretch goal would be to allow for defining groups of customer delivery addresses which share the same carrier account definitions.