I have some shared directories that I want to use to share files between two ubuntu computers (basically breaking up some processing in blender between two machines to improve rendering time). I can't seem to reliably write to the shared directories. It seems like it works when I copy individual files (one at a time) into the main shared directory. But if I try to copy more than one file at a time, it says permission denied. It also says permission denied if I copy a new directory with any sub-folders.

Ultimately, I want to be able to just seamlessly share files (as well as sub-directories and many sub-files) between these two computers on the same local area network. Is there an easier way to do this?