Systems developed and operated by different stakeholders are increasingly interconnected. When multiple systems collaborate in a shared environment and together provide emerging functionalities, they are referred to as systems of systems. These types of systems can be further classified by their level of centralized management and decision-making, reflecting the distribution of responsibilities and ownership among enterprises. This paper introduces two systems of systems architecting processes tailored to different levels of centralized decision-making. These processes aim to define the architectural design space, which is characterized by both the operations of the constituent systems and the composition of the systems of systems across various levels.