CNC power supply questions

Can switching power supply grounds of two diffrent supplies be
connected? The reason I ask is I hav a 24v supply for my steppers
and a 12v/5v supply for my indexer and drivers. The drivers have a
non-isolated common ground with between the logic and stepper
connections. If you need details please email me of list.

All help is appricated.

Thanks,

Shawn