the stepper controlers that i have
are?
it seems to work by having two control pins
Is it the stepper motor, your controller, or the library?
would it be possible to use something similar to the servo library to send out the neccesary pulses and keep the rest of the code "unblocked"?
No, because the pulses sent to a servo and the pulses sent a stepper controller are for entirely different purposes.
You can minimize the time that the library blocks by not trying to step more than one step at a time. Of course, this means that YOU have to determine when to send the next step instruction for each of the 6 motors.