[Paraview] Multiple grid zones in vtk file formats for ParaView

[Scott Martinelli]

Hello All,

I am in the process of writing my CFD output to a VTK file format, 
either the legacy or the unstructured XML format for use in ParaView. 
I would like to be able to select different zones of my grid (body surface 
versus flow volume) for the display of my output variables.

Is there a way to specify grid zones in these file formats?

I would prefer not to create two separate output files to be read in 
independently. 

Thanks for the input,

Scott