Logistics research has been emphasising the importance of interconnectivity for better resource utilisation and real-time response against disruptions. However, lack of trust has become a significant obstacle in the business world, blocking the way to building an open information system and, thus, more effective route-finding protocols. This paper proposes a decentralised routing protocol for multimodal transportation in a new logistic paradigm named Physical Internet (PI), performing under a privacy-protecting information-sharing policy. We seek the possibility of building a system to connect entities in a trustless environment that strictly limits data usage to the embedded services at a structural level. In the proposed protocol, the only service is to find the shortest path while minimising unnecessary data-sharing, with the potential to plug in more services. If no party initiates the routing, the entities remain in the equivalent state of disconnected. This routing protocol avoids sharing over 90% of the information in a simple scenario. In addition, a numerical experiment is performed to justify the quality of routes planned by the protocol.