Smart spaces incorporate a multitude of smart Internet-of-Things (IoT) objects to provide various services. Such devices immensely vary in their individual capabilities and are able to send/receive messages to coordinate among themselves to provide a non-intrusive smart experience for users. However, IoT-based services are limited to their individual features, which is induced due the lack of combinatorial capabilities for the IoT devices. As a result, smart spaces are restrained from the realization of a truly smart and connected world. In this paper, we propose the Composite Service Rendezvous as a Service (CSRaaS) middleware, which allows an immersive experience for users within a smart space. The CSRaaS component matches the service requests with the individual device capabilities, to create a new smart service by combining the features of multiple IoT devices. CSRaaS extends the notion of a conventional service matching scheme by coordinating the combination of published service capabilities to create new, unique, and on-demand service that best meets the user service request. We also present a prototype implementation which is used to perform experimental evaluation of the proposed scheme to justify the feasibility of CSRaaS in the real world.