Group work has been adopted as an important tool to support collaborative work in order to enhance learning processes. There is a wealth of literature related to group performance and the impact of group composition on group and individual performance. However, very few studies address the issue on how to automatically form groups. This article proposes a methodology that could be used by professors to form groups automatically taking into account different criteria as well as the students' profile. This methodology is based on a pilot study that analyzes group composition of self-formed student groups. The pilot study findings suggest that students tend to form homogeneous group in terms of level of the knowledge. Furthermore, students report that working on common topics of interests was a decisive factor in forming the groups.