A culture is defined that spans multiple retailers. Transaction data from the multiple retailers are processed to map barcoded item codes to a culture item vector space. Any non-barcoded item for a given retailer associated with the culture is linked to a most similar barcoded item of that retailer based on a retailer-specific item vector space. The distances between the mapped barcoded item codes of the culture item vector space are processed to cluster the barcoded item codes into classifications within the culture vector space. Each retailers non-barcoded items are associated to the classifications of the culture item vector space based on their linkages to the retailers' specific barcoded items, which are already mapped within the culture item vector space. Each item code of a given retailer's item catalogue is linked to its corresponding classification.