User per category restriction

This sounds complicated but what I meant was, … is there a way (plugin) to restrict certain users to certain categories. In other words:
– I want to set access to category A to user 1
– I want to set access to category B to user 2
– etc.

Only access to just one category would be just fine. I have been searching WP and the internet for this kind of plugin or script for a month now (on and off). Anyone ANY ideas?

TIA,

Eric