In this paper, we discuss and demonstrate the possibility of detecting multiple heartbeat of stationary subjects at equal distance away from a single input and single output UWB radar. To that end, we propose a novel concept to extract the heartbeat information from its harmonics to deal with the spurious peaks of respiration signal and intermodulations between respiration and heartbeat signals. We provide a numerical analysis to justify the proposed algorithm. We compare the ability of suppressing the interferencing harmonics between the proposed algorithm and other detection algorithms. Finally, we provide an experimental example and show that accurate heart rates detection from two subjects at equal distance can be achieved using the proposed method by comparing against two types of references: camera based system and chest heart rate sensor.