To me it looks like you've half got a parallel loop setup for the GPUs and half a serial. You might be better off asking PPMguire for help
Here's the idea if you had a fully parallel loop including the CPU:
You can leave the cpu as a serial connection though and just parallel the GPUs, but the general idea in the pic above should give you a better idea of what you're trying to do if you want to keep the para GPU setup.
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