Planar objects with opacity maps matteing out the fume smoke

[Suspensa]

I have a scene with steam coming out of a manhole with a series of planes in front of and behind the fume object, but not intersecting, with animated opacity maps to represent rain and also have a planar object along the road with animated opacity maps for running water that also dont intersect the fume grid (in 3 space anyways). When I render the scene, the fume smoke gets cut off by the planes. There is a visible line where it cuts it off. If i hide the rain and or water planes the smoke renders correctly. I've run into this problem before with objects with opacity maps. What causes this and how can I get around it?

Thanks,

Spencer