Multiple entities having the abilities of reflection can change their common environment individually by using the reflective operations in a metalevel architecture. In such an architecture, it is required to estimate how other entities are affected by the alterations caused by reflection. Namely, the propagation control for reflection should be defined exactly when one designs a metalevel architecture. We propose a formal definition for propagation control with the concepts of dependencies and propagation domains. We examine several existing metalevel architectures and system behaviours by using this formalization.