The texture token <shapename> provides a direct connection between the name of the mesh and the texture name, replacing the name of the 'shape' at render time.

Workflow

• Rename the textures to:

  main_BlueShape.jpg 

  main_RedShape.jpg 

• Add 'main_<shapename>.jpg'  to the image name of the file texture that is assigned to both meshes in Maya.

• Rename the meshes to 'Red' and 'Blue' and the textures will automatically be replaced.