Ultrasonic PING: multiple trig on single dig. pin This may seem a little stupid, i apologize  if so as i'm new to electronics/arduino.

I have 4, 4-pin ping sensors. I'm running out of available pins on my UNO.

I had a ponder &amp; wondered if it was possible to link all 4 sensor's trig pins to a single digital pin, with the echo pins assigned to their own pin. In my head, on each sensor call (sorry i'm used to programming terms) all 4 sensors would send a pulse, then only the sensor (or echo pin) in question would be read. Is that plausible? each ping sensor is about 20-30 cm separated, but facing internally, in a spiral downwards.
I was able to achieve the result using my suggested method in the question. 
As BrettAM stated, the signals are wasted on the other 3 pins when checking 1.
This solution was suitable as a proof of concept