Add Vendors Sublist to a Matrix Subitem record

Add Vendorssublist to Matrix Subitem record 

1.   Navigateto Setup > Company > Enable Features> Items & Inventory.

2.   Onthe Items portlet, mark the MultipleVendors check box.

3.   HitSave.

Note: This will let you add multiple vendors for a matrix item subrecord and choose the Preferred Vendor for that sub record.