dual Z axis setup questions

I like to inquire with the user here on the zone, To develop, a how to blog setup...... as to how to set up dual Z axis using mach.

Im looking for advice... ideas to develop dual z axis using water cooled spindles.

It would helpfull if user can post sample code and photos of there setup, or video of there systems

Can someone explain what need to be done in mach, to support 2 z axis.