Index only encoders for X and Z on 7i43

I am thinking about putting indexes on the X axis and the Z axis of my lathe to assist in homing.
Pncconf seems to not support index only encoders for axis other than the spindle. Am I missing something?
Is there a way to do this in the 7i43 configs?
Does the 7i43 bitfile SVST4-4 support index only encoders?

Not sure what you mean by index only
Do you mean a single pin encoder that's both "A" and index?

HM2 encoders wont do this but you could certainly do it with a software encoder on a GPIO
pin ( with the encoders components A and index inputs wired to the same GPIO pin )

I am basically talking about mounting a disk with a hole in it and an opto-sensor to function as a single index (or I guess index and channel "A").

So is the software encoder a kernel module that gets loaded like follows:
loadrt encoder num_chan=1

You also have to addf the functions to the threads. (and you probably will need a base thread.)
addf encoder.update-counters base-thread
addf encoder.capture-position servo-thread