This study examined the influence of group structures upon six groups of distributed graduate students as they pursued a six-week problem-based learning activity by communicating in an asynchronous computer conference. Henri and Rigault's (1996) content analysis framework and Howell-Richardson and Mellar's (1996) guidelines for interconnectedness of messages were used to analyze the messages. In addition, learners' perceptions of interdependence and intersubjectivity were gauged from a self-reported survey developed by the researcher. Overall comparisons revealed that group conferences with role assignment had higher levels of interconnected messages. Weekly comparisons also indicated higher perceptions of intersubjectivity and deep processing for the role assignment group during the initial weeks of the activity. Over time, however, these levels equalized across group structures.