Based on a longitudinal case study of four interorganizational product development collaborations, this paper identifies a lure to cross‐functional integration that has hereto been neglected. In particular, findings suggest that when the buyer firm separates the Research and Development (R&D) Department from the Procurement Department, the two departments play a good cop–bad cop strategy toward the supplier. Thereby, they are able to foster a high level of goodwill trust between R&D personnel of the collaborating firms, while procurement personnel maintain a high level of formal control. Using an intricate sample design with polar cases, the study shows that cross‐functional integration of the two departments hampers interorganizational goodwill trust at the benefit of formal control. The findings offer a way forward for managers seeking to reap the benefits of collaboration, while limiting their exposure to the associated risks.