Decision-making groups collectively have a larger information pool than any individual within the group. When groups employ group support systems (GSS) for discussion, task-relevant information that is common to all is exchanged more frequently than information that is unique to one person alone. Not only that, GSS groups also exhibit a lack of information processing with regards to unique information that members contribute during group discussion. A laboratory experiment was used to evaluate (1) the level of information exchange in GSS groups and (2) the effects of expertise role-assignment on the pooling and processing of unique information in GSS groups given two different pre-discussion information distributions. Forty-eight 3-members groups participated in a group judgment task, which required them to decide the most likely murderer from 3 suspects, in a murder case. Results indicated that regular GSS groups tend to pool more common information and partially shared information as compared to unique information. When role-assigned, GSS groups pooled more unique information during discussion and retained more unique information after discussion than non-role-assigned groups. As a result, role-assigned GSS groups had sufficient information to identify the most likely murderer in the murder mystery, as compared to regular GSS groups.