Insteon or Z-Wave integration

So, recently I had the idea of finding a way to combine my old, wired security system with my new Insteon system. I was wondering if there was a way to interface Arduino with either Insteon's through-the-wall system (which I highly doubt will work) or with Z-Wave, which I am more hopeful for.

I was looking into this SmartThings shield, which I believe utilizes Z-wave. However, I also think that it's only compatible with the smart things system, which I do not own. If there are any kinds of shields similar to this one that is compatible with any generic Z-Wave system, then I would love to know about it. Thank you.