Machine-Type Communication (MTC) Systems play a critical role in providing ubiquitous Internet of Things within the emerging 5G technologies. We consider an MTC system with a massive number of devices and provide a hybrid scheduled and group-based random access solution for accommodating the massive traffic. We study the proposed solution through a spatiotemporal analytical framework, where we use stochastic geometry, probability theory, and iterative algorithms to derive the frequency of successful transmissions and the expected queue status at the devices. The analytical model is then used to study the stability-scalability trade-off in the proposed scheme.