Merge PBO with multi gpu


I m work ing on a OpenCL / Cuda application and for each gpu I generate an image.

I would like to create à PBO for each GPU and be sure that each PBO is located on a specific GPU.

  1. question 1: how to create à PBO on a specific GPU ? Is it possible ?

Once done I would like to merge the PBO (do a simple average of the pixel color) and display them.
2) question 2: how can I merge all the PBOs and display them… What is the best solution ? Using GLSL ?

Thanks a lot for your help