P.S.: since I did not found a file in the Drop-Box, here is another file, based on your addition information.
Here is a file with 3x3 cubes, all “faces” have a different image (well it would require 162 images, but the example has 91, I guess it shows the idea)
The reflection is made more visible via bump, to differentiate it from the background.
The MoGraph Multi shader can be used of course in Color channel as well.
The Random Effector is placed in the first cloner, so each following stage has that information.
The Plain Effector pushes just the “faces” (the polygon object/clone) away from the cube, to separate the (surface/texture) information. Switch it off to see the resulting problem. This could be handled with a Polygon, editable, and the axis moves.
Scene file: …_21.c4d
Of course the simplest way, not per se the fastest, is via polygon selections. …_31.c4d
A very short way is this one, but typically the Formula Effector stops people. So, the Formula just gives each single polygon object a slight different brightness value. For that to work, the Cloner Object needs to be set Transform>Color>Black
Scene file: …_41.c4d
As usual, I try to show several options, to allow for exploration and judging what would be the best in a given situation, or just – what feels better. OI hope it allows for more freedom, instead of sharing one set up and call it a day.
Let me know if you miss something, I’m happy to look into it.
All the best