Investigating the participant structure that works in online courses helps us design for, and facilitate, collaboration. Learning communities and group work influence collaboration in online courses. We present an exploratory study of computer-mediated groups that used this model to participate in an online MA program in Educational Technology. These participants were organized into groups and collaboratively built knowledge through synchronous and asynchronous online dialogue while leveraging technology as a tool for individual and collaborative learning. We present a detailed case study collected over a two-year span to identify design ideas, structures, and perceptions of effective collaboration and performance. Group formation, support, and sustainability are also explored. Examples are included that not only describe what participants saw as enabling aspects of the structure but also ways in which novice instructors can enhance curriculum development around readings and online discussion. These findings indicate a high index of collaboration and completion compared to homogenous classes where students work on their own.