Hi, I want to know if it's posible to do something like this in repetier firmware
I do not understand exactly how it works since I do not speak the language, but I think it should be possible. Looks like 1 motor output is copied 3 times and only one is active depending on some state of pins. We have a select and deselect gcode per extruder which you could use with M42 to set the combination to activate right motor.
Thank you do you know how to conect the Relay 8?
No. As I said wrong language and don't have the hardware.