To manage coopetition, two principles have previously been highlighted in the literature: the separation principle at the organizational level and the integration principle at the individual level. But less attention has been paid to the working-group level. In this chapter, we describe an original organizational mode designed by coopetitors to achieve innovative but risky projects: the coopetitive project team (CPT). Within a CPT, coopetitive tensions are managed using a third principle: the co-management. We thus argue that the efficient management of coopetition relies on the combination of three principles: separation at the organizational level, co-management at the working-group level, and integration at the individual level.