Ok so I downloaded multimap exporter and tried it out and it did work as advertised. I now have nine separate 4k displacement maps
. one for each uv tile on my model. Score! 
But… 
Now my problem is in the incomplete information on the web on how to utilize multiple displacement maps on a single mesh with separate uv tiles in Maya.
The tutorial I linked to said to apply the displacements to the uv islands by selecting them in the uv window > convert selection to faces and then applying the displacement shader. Then I can have a single displacement shader on each uv tile. There is critical missing information here. Even the pic does not show the real connections in the hypershade.
When you apply a single shader to each UV tile of polygons, like say a phong, you will get separate shaders for each part which is good.
The problem is that when you graph materials on selected items (the whole mesh) you will see all the shaders but only one SHADER GROUP.
This is critical for displacement map usage and I’ll tell you why. No matter if you are using mental ray or vray or final render or renderman, ect., you need a shader group to plug a displacement shader into. If, like the bulldog tutorial here at Zbrush site I linked to, you just apply a displacement shader to each uv tile it will kick the phong shader off the model and apply the displacement shader in its place. So when you render in mental ray the plygons wont be visible. So you go back and apply the phong shaders to each uv tile area and they all show up but now you will only have one displacement shader attached because there is only one shader group with a displacement slot.
Now, say you wanted to use layered texture to apply all 9 displacement maps. The problem here is that if you use the “wrap u wrap v” on the texture locater node method (like the tutorial shows) for getting the texture to continue on down the UV tiles in the UV window you run into another problem. How do you keep all the textures from repeating on top of each other? Is there a way to say to each texture "only show up between uv space 2-3 per texture?
This is where I am stuck currently. I can’t figure out a way to have 9 displacement map shaders attached to a single mesh that also has 9 phong shaders as well due to the shader group limitation.
I am not aware of a way to have 9 shader groups on one mesh.
Thanks for any info. This kind of displacement map setup is not well documented on the web at all.
