You'll sure get them once we're done with a couple of more issues
1) The Group id mask works fine, however I see no way to change the order of chunks (i.e. sort ids: along XYZ axes, radially, randomly?)
2) A good fracture scene requires at least 2 materials and 2 uv maps: inside and outside. I've made a simple scene in blender with 2 embedded textures (for clarity). The fractured mesh (meshes to be more precise) is on layer2. You can export the chunks as an fbx using the fbx export plugin included in blender (I can't remember if it's on by default).
As @lamogui said:
IMO we need some solution enabling users to use more than 1 material per referenced mesh. You can use my file for testing. fracturecube3.zip (2.6 MB)
P.S. You can get the latest blender release from here