Ability to assign cells to different processes using their gids

[tjbanks]

Hey all - I have a unique situation where I would like to to assign cells to specific processes due to (potential) network lag. An example situation may be where I have two regions that communicate often on one host but occasionally communicate over the network. I think I see where cells are assigned here: https://github.com/AllenInstitute/bmtk/blob/develop/bmtk/simulator/bionet/bionetwork.py#L192

But want to be sure that my thinking isn't off and ensure that I can't already assign process via gid.

Thank you again, Tyler

Cc: @V-Marco