Carrying out collaborative learning activities (supported by technologies or not) typically involves the coordination of multiple participants, in their dynamic assignment to groups and roles and in the distribution of resources and tools to specific group or individuals. While the mechanisms required to address these coordination aspects in digital educational spaces have been largely studied, less research has been conducted on orchestration support for facilitating this coordination in (technology-enhanced) physical spaces, such as the classroom or the playground. This paper presents the Signal Orchestration System (SOS), a system that augments the physical environment with digital signals indicating orchestration aspects. The SOS facilitates its integration with digital educational spaces to allow transitioning activities from digital to physical spaces. The paper describes the SOS system and its underlying architecture through a functional prototype that has been developed to show its feasibility and to enable its evaluation in authentic situations. The main components of the prototype include a Manager, where orchestration visual and auditory signals are configured, changed on the fly and transmitted, and three different designs of Wearable Signaling Devices, which are carried by participants and render the orchestration signals. The prototype has been used in two different experiments in the context of a real course applying adaptations of the well-known Jigsaw collaborative learning flow pattern. The results show that the SOS enables a flexible dynamic orchestration of the collaborative activities.