In warfare modelling and simulation (M&S), the mission assigned to an aggregate unit, such as platoon, company, battalion, etc., is achieved by the military operations that the unit's subordinates perform. In this procedure, the tactics for achieving the mission play an essential role for the aggregate unit to translate the abstract mission statement into concrete military operations to be performed by its subordinates in consideration of the dynamically changed warfare situation. However, the practical component-based warfare M&S software does not provide a model to explicitly represent such tactics. In this paper, we define ROle-based Command Hierarchy (ROCH) model for users to formally represent the tactics of units at design time and develop ROCH framework to support that an aggregate unit dynamically assigns roles to its subordinates considering their situation at runtime. Then, we discuss the benefits of our approach from the perspectives of composability, reusability, adaptability, and scalability.