One alternative along the lines of what
Jraef mentioned is below and uses commonly available parts:
Use an appropriate contactor and a start/stop switch for each of the 5 motors, but with the same coil voltage in all of them (for example, either 120V or 208V).
3 SPDT switches are used to select which of the motors can be activated by their local start/stop switch. The connections below will also not allow either 3PH motor contactor to be turned ON with its start switch unless the contactor for the phase converter is turned on first with its own start switch.
Switch 1:
Common terminal to 120V line
Position 1 selects 1PH motor operation. Supplies 120V to the switch 2 common terminal.
Position 2 selects 3PH motor operation. Supplies 120V to the start/stop switch for phase converter.
Switch 2:
Common terminal is supplied with 120V when switch 1 in position 1.
Position 1 selects 1st 1PH motor. Supplies 120V to start/stop switch for this motor.
Position 1 selects 2nd 1PHmotor. Supplies 120V to start/stop switch for this motor.
Switch 3:
Common terminal connected to the start/stop switch output that activates the coil on phase converter contactor.
Only at 120V when phase converter is running.
Position 1 selects 1st 3PH motor. Supplies 120V to start/stop switch for this motor.
Position 1 selects 2nd 3PH motor. Supplies 120V to start/stop switch for this motor.
If the switches are physically located as below I think it would mentally simplify the selection of the different types of motors, because switch 2 is enabled when switch 1 is UP and switch 3 is enabled when switch 1 is DOWN:
Switch 2
Switch 1
Switch 3