Tunnle between two res'

I was wondering if it is possible to have a hole/tunnel between two res’ if you own them both? I know dynamite would probably knock a hole through the path underground keeping the path itself in tact if you set it deep enough but did not know if this was allowed?

Over the 127 block height you can build out 2 blocks onto the road. This would allow you to connect two residences as long as it was over a four wide road.

I thought with one of JustinGuy's fixes, there was no interference at all over the pathways?

There wasn't last time I checked, though he may have updated it.