In recent years, an increasing number of blockchain consortia have emerged. However, little is known about how these consortia are developed and what tensions emerge in such collaborations. We describe the evolution of the cardossier blockchain consortium in Switzerland, which is building a system for managing car data and seeking to improve collaboration between players in the car-related ecosystem. From our involvement with the cardossier project, we have gained insights that will be valuable for enterprises considering whether to join a blockchain consortium.