The efficiency of software engineering processes is highly dependent on the level of coordination and collaboration inside the engineering teams. Even though the serious efforts to standardize and capitalize practices in order to enhance software engineering processes, we are still in need of a more efficient way to manage concurrent and collaborative engineering. This problem became more obvious with the emergence of global software engineering requiring the coordination of international teams. The question of collaboration has been studied on many levels: Internal versus external collaboration, mutual versus exclusive collaboration... While there are practical solutions to improve teams' coordination, a consistent approach integrating collaboration in the early stages of the software process engineering is still required. In this paper, we consider the impact of coordination and collaboration on the efficiency of processes and identify three main goals for a solution to meet: Process state management, process orchestration, and process validation. Then, we propose our solution COLSEF (COLlaborative Software Engineering Framework) as a consistent and global solution constructed around a metamodel for software process engineering. The current paper will cover the foundations of the solution through its core metamodel and the implementation of its orchestration engine.