This paper reports on a case study conducted to guide the design and implementation of a group support system. Network analysis of student self-reported interactions was conducted to obtain a better understanding of social relations, which are critical in informing the design of systems that support sociability. Building on previous research on group dynamics, the study examined the impact of negative relations and frequency of communication on performance and satisfaction among 13 groups of students. Results show that group members disliked by others were less likely to perform well; group members were less likely to feel satisfied with the group process when they disliked others; and frequent communication with others could make a person more likeable and help him/her perform better. We conclude by providing suggestions about how to incorporate findings from network analysis into the design of communication technologies to support group work.