I want to make a 3d plot with FaceGrids with a certain color scheme. Specifically, I'd like them to be one color below a diagonal line, and a different color above it. (So for example, on the y=0 surface, I'd like the FaceGrids to be pink below x=z, and blue above x=z.)

If I were coloring the plot itself, I'd define a ColorFunction, but it seems that FaceGrids doesn't take ColorFunction as an option. Here's an example of my best attempt:

    Graphics3D[Cylinder[], 
     FaceGrids -> {{{0, -1, 
         0}, {{{-1/2, ColorFunction -> Function[{x, y, z}, Hue[z]]}, {0, 
           Green}, {1/2, Blue}}, {-1/3, {1/3, 
           Directive[Thick, Dashed]}}}}}]

Note that while the other gridlines have the properties assigned, the one with a ColorFunction is just gray.

Is there any way to have varying colors on FaceGrids?