Collaboration has long been considered an effective approach to learning. However, forming optimal groups can be a time consuming and complex task. Different approaches have been developed to assist teachers allocate students to groups based on a set of constraints. However, existing tools often fail to assign some students to groups creating a problem well known as "orphan students". In this paper we propose a framework for learner group formation, based upon satisfying the constraints of the person forming the groups by reasoning over semantic data about the potential participants. The use of both Semantic Web technologies and Logic programming proved to increase the satisfaction of the constraints and overcome the orphans' problem. (Contains 3 tables and 4 figures.)