AIU and Z Stuff Signals

Hi

i have some z stuff signals which are activated by touching the input to ground. When the input and ground are touching, the signal goes red. When they stop touching the signal cycles thru yellow to green. They are also activated by trackside infared.

My question is, how should I connect these signals to my AIU to be able to activate via DCS while still retaining infared control.

For what it's worth I have red 'hot' and black 'ground' wired to a separate accessory transformer (along with several other similar signals)

Thanks