How do I mask out Fluids in a hardware render?

[phalimjinx]

"Hi Everybody!" 
(best Dr. Nick impression)
I am running a sim that uses Sprites and fluids. How do I mask out the fluids in the hardware render so I can make sure the sprites behind the fluid (as well as the sprites in front of the fluid) will composite correctly? 
In other words, I'm looking for a way I can put a black hole shader (or equivalent settings) on the fluid for the hardware render.
Anybody have an idea?
Thanks in advance!
-G

[joojaa]

can not be done, use software render and a particle instancer

[phalimjinx]

Awesome again, Joojaa.
Cheers!