The order in which user stories are implemented can have a significant influence on the overall development cost. The total cost of developing a system is non commutative because of dependencies between user stories. This paper presents a systematic and lightweight method to identify dependencies between user stories, aiding in the reduction of their impact on the overall project cost. Initial architecture models of the software product are suggested to identify dependencies. Using the method proposed does not add extra load to the project and reinforces the value of the architecture, facilitates the planning and improves the response to changes.