Thanks PaulS.
Actualy I do have one version where I can command any combination of the 3 steppers to run in stepmotor, using a mask like if(motornumber & motorId). The limit is that they must make the same number of steps.
I do use stepper drivers that need direction and step. (Enable also). One version of them is a Protooner board and the other version is a Micros Driver 6650(?), answering to the same signals.
Are there any more intelligent drivers that would accept Direction and number of steps? That would release my UNOs from waiting.