Electronic – arduino – Measure distance using an ultrasonic sensor in a pipe

The URM37 appears to be a typical "ping" module and does not have two sensors, rather it has a transmitter and a receiver.

You could build a system with one transmitter and two receivers if you got into the details of amplifying and detecting the signal yourself, rather than relying on the module to do it.

You might be able to slave additional modules to the primary one by removing their transmitting transducers and firing them all at once, though the circuit might misbehave without some loading.

The easiest solution would be to use multiple modules and take turns firing them so that they don't confuse each other. Just take the normal measurement interval and double it so that you are taking a measurement at that rate, but each sensor is firing half as frequently.

The SRF05 sensor is designed to give a pulse indicative of the time it took to receive the first reflection of the US signal. Hence when a nearby object is present a more distant object will have no effect at all on the 'official' output.

Somewhere on the PCB you can tap into the raw received signal. You could process this yourself. If the more distant object produces a US reflection it will be observable in this signal.