Very interesting :)

Using materials in Bryce, you may not be able to do this, but if you think outside the box, maybe you can just use your water material, and then make a grouped object, setting the object that has the water material applied positive, then creating a random array of spheres, set as negatives against/inside the water object, maybe apply a glass material to those...

Just a thought, havent put it to practical use as yet :P

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