The importance of acquiring and maintaining teamwork skills for high team performance is well documented in both academic literature (e.g., Sottilare, et. al. 2017; Wilson, et. al., 2007) and military doctrine (e.g., ADRP 6-0, 2012).  However, effective training of teamwork skills (as opposed to task skills) has remained a challenge.  To maximize training effects, while reducing costs, and increasing reusability, there has been a push in the military toward using intelligent tutoring system (ITS) frameworks, such as the Generalized Intelligent Framework for Tutoring (GIFT; Sottilare et. al., 2012; Sottilare et al., 2017). The majority of ITSs are designed to train individual skills rather than teamwork skills, since there are both theoretical and technological challenges associated with developing ITSs for teams (Sinatra, 2017; Sinatra, 2018).  While there have been implementations that extended ITSs to team-level training (e.g., Bonner, et.al., 2017 extended GIFT to 2-3 person teams), challenges in scaling to larger teams (e.g. 9 person teams), providing realistic training environments and scenarios, and measuring teamwork skill acquisition in both real-time and after the fact remain.  This paper describes the design and implementation of an extensible system for training teamwork skills within a realistic simulation environment.  This includes development of doctrinally-relevant military scenarios within Virtual Battle Space 3.0 (VBS3), strategies for measuring teamwork process and state constructs (in particular, coordination and cohesion), and training feedback strategies for delivering both individual and team feedback.