Special Orders and Picking suggestion

Our client has new requirement - The stock is manufactured with same lot and item, and they are further differentiated as old items and new items. For particular orders raised by 3 customers, the new items has to be transferred and the process from order to creation to storing in the warehouse locations will be manual. Few locations in the warehouse has to be utilized only for these special orders. The requirement is system has to suggest picking only from this locations for that particular orders. The current warehouse management system we are using is based on location categorization based