My understanding is Mach3 does it automatically when it sees separate pin assignments for the limit switches. Are yours going sequence? I'm in the process of redoing my limit switches to be independent so first hand knowlege is only to the point where my buddies CNC Bridgy homes independent.
I'm going to be mighty disappointed if my modification doesn't work.
Ok, I'm a little dumbfounded. I just temporarily jumpered in my limit switches and Mach3 is NOT homing the X and Y at the same time. I'll could have sworn that I have heard at different times that this was the case. I'll need to look into this a bit more.