Best way to network render with a mixed GPU/CPU farm?

We have a small render farm here at office, some with capable nvidia GPUs, some without. I use Afanasy for my netrender manager and usually just do cpu network rendering. It works flawlessly, but I REALLY want to take advantage of those GPUs. The problem is that CPU and GPU rendering both require different render settings and I want to just send the job to the farm and have it be able to automativally use the gpu when available and use cpu when it’s not.

Any idea how I can do this? Is there some kind of command line flags I can set to enable this?