Counterfeits and contaminated drugs are recognized as a threat to consumer safety. To fight counterfeiting and protect consumers, public health institutions such as the US FDA demand organizations to electronically document the pedigrees of prescription drugs [3]. As the documentation process involves joint collaborations of multiple organizations along the supply chain on electronic pedigrees for billions of individual goods, new and scalable access control models are needed. Therefore, this paper presents a novel concept, which leverages existing organizational relationships to manage access control based on physical possession. The concept is evaluated against other existing models and discussed.