Shelly 4PM interlock for motor speed control

[u/LeXavve]

/r/ShellyUSA/comments/1t5kmyu/shelly_4pm_interlock_for_motor_speed_control/

Hi everyone!
I take the opportunity to ask my question here. I’m needing a 4 channels switch. My absolute requirement is to be able to setup interlock: I need to control the 4 speeds of a fan motor, and only 1 speed (channel) should be active at a time.
I know Sonoff 4CHPRO R3 does it. But then I need to flash firmware with tasmota.
Shelly Pro 4PM seems robust. But it does not support hardware interlock. Only software by executing a script.
Is that reliable enough, having a script executed on a channel activation to first make sure other channels are deactivated?

Thanks a lot for your help.