The paper presents a comprehensive approach using radar technology for non-contact vital sign monitoring, focusing on multi-subject scenarios. By leveraging a Multiple Input, Multiple Output (MIMO) radar configuration with Direction of Arrival (DoA) methods, along with digital beamforming, the Generalized Sidelobe Canceller, and a frequency tracing technique, the study achieves impressive accuracy with a mean absolute error of less than 3 BPM, even in challenging situations. This radar-based vital sign monitoring shows promising prospects for precise and non-intrusive healthcare applications.