Requirements specification is one of the most important phases in developing a software application. In defining the behavior of a system, requirements specifications make use of a number of scenarios that are interrelated in many ways. Most of the current approaches, even though giving directions on how to translate them into state machines, treat each scenario separately. Because different relationships between scenarios result in different state machines, we believe it is significant to emphasize and represent these relationships. In order to illustrate them we propose a new type of diagrams named dependency diagrams. We offer a set of rules and steps for the synthesis of state machines from multiple inter-related scenarios, based on the initial scenarios and on the newly introduced dependency diagrams, as a means to describe the requirements specifications and to offer support during the design and implementation phases of developing a system.