The primary purpose of this study was to examine and describe, through the lens of nexus analysis, how social action impacted the compositional processes of high school string students as they engaged in collaborative composition. In this study, I examined the complex convergence of verbal and non-verbal communication while students were engaged in music co-creation and how it impacted social practices such as rules, roles, or division of labor. Specifically, this qualitative study investigated the following research questions: (1) How does social action impact the compositional processes involved in co-creation? (2) What roles, social structures, or social identities do students who are engaged in musical co-creation assume? The participants in this study included eight high school orchestra students who participated in ten after-school small group music composition sessions. Each session was 45 minutes in duration and occurred over an eight-week period. Additionally, students participated in two individual semi-structured interviews and two semi-structured focus group interviews. The participants in this study adopted an interaction order they referred to as The Circle. This global concept consisted of a set of rules for behavior, interactions, and democratic guidelines. It provided a social safety net of acceptance for each member of the group. An underlying theme of The Circle was the goal of achieving equality within the group regardless of previous musical experiences or expertise. The following data were analyzed: (a) students’ responses, processes, and behaviors (both musically and verbally) that occurred during the collaborative activities; (b) students’ verbal responses to questions in both individual and focus group interviews; and (c) field notes and artifacts that were examined to reveal any relevant data. A common theme throughout the study was the adoption of multiple roles. Participants in this study assumed four different roles: follower, advocate, tutor, and leader. Only two members retained a single role for the duration of the study while the other six girls assumed multiple roles depending on the needs of the group at a specific moment in time.