For drop shipment process, cart method 'createDropShipGroups' only check requirementMethodEnumId at Facility Level and Product level. Also, found the unhandled case of not considering requirementMethodEnumId at Product Level if this property found at Facility level.
RequirementMethodEnumId should be decided in the order of property set at ProductStore -> Facility -> Product.
Check and enable drop ship PO if 'Drop-ship Only' property is set at Store level. Also, this property should be checked and override at Facility level if exists to consider the case when Facility does not allow drop ship Order. Finally, it should be checked at Product level to consider the case when Store and Facility allow for drop ship but the product does not.