Not sure if that is possible as Daz is using iRay, right? That is a completely different kind of render engine than the game engine that iClone pretty much is. iClone like Unity and Unreal pretty much want the beefiest single GPU you can throw at them. What they might be able to do is split calculations and have one GPU handling rendering duty and the other handle simulations and such.
Another thing that would be sweet but might also not be possible with their engine is out-of-core geometry and textures. So if you hit the limits of your GPU memory it can cache out to system memory. I have not seen this supported in game engines yet. Not sure if consoles can do this.
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