Star / Delta switching

Hello,

I need switching spindle into star / delta configuration depending at speed. Simple it means this steps

1) if spindle speed is changed
2) check if spindle running -> if running then stop it and wait to 0 rpm
3) if speed is below 2000 rpm switch on 2 outputs relays otherways switch off relays than wait for example 0.5sec
4) if spindle was running -> power it and run at desired speed


Question is what is it best way to do it.
I mean whitch part of linuxcnc is best for this Ladder, Hal, Gcode macro?

The condition is that it is independent of the user. User must simple set speed and machine must do it yourself.

Thanks Michal

Response is simple remap S code