MultiStepper and MultiStepper speed adjustment

All,
I have created a process that passes 3 values via serial port to control my arduino / steppers.
the serial in is 200:400:10 where the string is parsed out as ‘:’ delimited

MultiStepper steppers;
steppers.addStepper(motor_X);
steppers.addStepper(motor_Y);

positions[0] = 200 (X_stepper position) << works
positions[1] = 400 (Y_stepper position) << works
and the 3rd value 10 should be the speed of X << not sure how to apply a speed in the array passed to the steppers.???

steppers.moveTo(positions);
steppers.runSpeedToPosition();
Serial.println(“OK”);

positions is an array for position but I need to pass a speed parameter to the MultiStepper

any ideas? and yes I have read the documentation and NO I do not want anyone to write code for me.
any constructive ideas are appreciated

I use the setMaxSpeed() function to set the speed of each motor.

A snippet from my plotter program

if (gCmd == 0)  // move at full speed (travel) G00
      {
        xMotor.setMaxSpeed(motorSpeed);  //max speed for travel
        yMotor.setMaxSpeed(motorSpeed);
        moveMtrsTo(xCmd, yCmd);
        gCmd = -1;
      }
      else if (gCmd == 1) // move at set speed (feed) G01
      {
        xMotor.setMaxSpeed(fCmd);  // incoming feed speed
        yMotor.setMaxSpeed(fCmd);
        moveMtrsTo(xCmd, yCmd);
        gCmd = -1;
      }

let me try that... if I globally set the speed and add them to the MultiStepper.. the speed is persistent and I cannot change it motor_X.setSpeed(getStringPartByNr(toMove, ':', 2).toInt()); //get the 3rd value in the 200:200:30 steppers.moveTo(positions); never picks up the new speed setting

thanks

From the AccelStepper library moveTo reference.

Set the target position. The run() function will try to move the motor (at most one step per call) from the current position to the target position set by the most recent call to this function. Caution: moveTo() also recalculates the speed for the next step. If you are trying to use constant speed movements, you should call setSpeed() after calling moveTo().

The MultiStepper library uses only constsnt speed movements. No accel.