(Python) Is there a way to Parallel Render with VTK?

I am trying to follow the example showed here: https://gitlab.kitware.com/vtk/vtk/-/blob/v9.1.0/Examples/ParallelProcessing/Generic/Cxx/TaskParallelism.cxx
to allow me to parallel render a vtkMultiBlockDataset, the data is already distributed across multiple nodes and I can open N render windows and interact individually. Now I am looking for a solution to render only one window with all the data from the other nodes. However following this example alone did not work for me. I get an error if I try to do ‚Äúcontroller.SetSingleMethod‚ÄĚ and if I just let every call the process function in all processes I end up with N empty black windows.
Is it possible to render in parallel in VTK and where can I find documentation to do this?
Thank you.

openGL seems like not allowing multithread in single window.