Ric,
are you saying is there is a switch fixed mid axis and it is triggered at either end of the axis? And additionally there is another switch on each axis that triggers close to the end of axis?
If so then that is the normal configuration for industrial machines. One switch is a home switch and it is used to signal the control to search out the index pulse of the encoder for homing, the other is a limit which is to stop the axis immediately should it over travel.
In Mach you can have a similar setup, ie one switch per axis and have them all tied together in series and using one input. You can configure them as both limits and home switches in Mach. When homing the switches are treated as home switches, all other times they are treated as limits.
I personally prefer to have separate home switches and I home to my servos encoder Index pulse, for that however you need to have servo drives or a controller that supports the function.
Hood