Yes of course. If you want several steppers run exactly the same you can connect them in parallel to the same pin. It makes no difference if you use separate OCnx pins for this purpose. It only uses more pins.
N.B. I think you use a step/dir driver. In this case only the leading edge makes the motor do one step. Why use the 'toggle' function with OCRxn? You don't need a sqare wave. A short pulse with constant length and variable repetition frequency will do the job.
When the Counter is reset to zero the output can go HIGH, and e.g. OCR3B at a constant low count resets it to LOW. OCR3A then defines TOP which sets the repetition frequency. You get only one interrupt at every step, which should be sufficent.