Hi, If I’m understanding correctly I think there is a trick that can work for this to use the color attribute to mix multiple shaders.
If you set the each inflow to either pure red (1, 0, 0), green (0, 1, 0), or blue (0, 0, 1), the RGB channels can be separated in the shader and used as a mix value.
Here is a .blend file with the set up:
mixing_shaders_with_rgb_channels.blend (2.6 MB)
This should work for mixing up to 3 shaders together (1 shader for each RGB channel). I’m actually working on a feature right now that is similar to this technique for mixing more than 3 shaders and this will come in a later update.
Hope this info helps!