RSSI or Power measurement of AM/FM signal with RTL SDR fm receiver

Hi, Currently, I am using RTL-SDR FM Broadcast Radio example came with Matlab Simulink by default. In that example, I am more interested in measuring the RSSI of FM signal to see the power/noise of the signal in dBm. For example, if I listen to FM radio at 102.5MHz, I want to measure the power/noise (dBm) of the centre frequency at 102.5MHz. could you please suggest how I can do this in Simulink?