Importing multiple subsidiaries for a single vendor

Solution

1. Create a CSV file containing 2 columns: Vendor Internal ID, Subsidiary Internal ID
2. Navigate via Setup > Import/Export > Import CSV Records
3. Set the following in Import Assistant: Import Type: RelationshipsRecord Type: Vendor-Subsidiary RelationshipData Handling: Add or update other changes that are needed in the Advance Options
4. Field Mapping step: Fields should be automatically mapped. Else, Vendor Internal ID should be mapped to Vendor and Subsidiary Internal ID to Subsidiary. Set the Reference Type of both fields to Internal ID.
5. Set Import Name.
6. Click Save and Run.
   Note: The Vendor-Subsidiary Relationship record is not visible in the user interface. The fields available for mapping appear in the header of the Vendor record, and on the Subsidiaries subtab.