To realize context-orientation in concurrent systems, especially in systems based on asynchronous communication, we must take special care to control synchronizations among context changes and other computations. In this paper, we present a method to construct a reflective architecture for a group of actors and describe the method to implement concurrent context-oriented systems. The key idea is to apply parallel composition to actors that constitute the meta-level of the group. This results in a uniform construction method for various types of meta-level actors. Using the method, we give a solution to a synchronization problem regarding cross-context messages.