Are process interrupters the proper way to accomplish this
No.
And if they are the best way, how would I wire/program multiple versions into one system?
It is straight forward to do one system but for multiple systems you need to use a state machine.
See my
http://www.thebox.myzen.co.uk/Tutorial/State_Machine.html
Or Robin2's several things at once
http://forum.arduino.cc/index.php?topic=223286.0