Abstract. Given a set of observations of an existing concurrent system with repetitive sub-functions, we consider the construction of an MSC graph representing the functionality of the concurrent system. We first introduce a formal structure that we call ”lattice of repetitive subfunctions”. This lattice provides us with a global view of all the repetitive sub-functions of the system and all the compatible observations. Using the lattice, we are able to propose an algorithm that constructs the MSC graph representation of the system functionality in a more general context than in previously published work.