Grant access to nodes of particular user

I'm currious if there is possible to restrict access like in following example:

A site where some content is free to see and some other restricted only to some groups. Some user, lets say Editor would have right to create content and some group of users would have granted access to his nodes. There would be more users like Editor and each group of users would only get access to selected editor-user.

I thought about using taxonomy access for this, so that every used like Editor would have his own term which he will select on his node. But then I would need to restrict him to only select his term and not others (dont know how). I tried to use Action module, and Workflow to automatically add taxonomy term to a node when created, but weirdly there doesn't seems to exist such functionality in those modules. Thats where I get stucked. Any thoughts? Maybe this could be done be some simpler solution, but I just can't think of any.

Note: I don't want to use different content type for each editor-user (and use Nodeaccess module), because I already have some created and it would be too messy to create one for each user with editor rights, not to mention all node types are all customized by CCK and contemplate. I also tried Organized Group module, but I dont have many experience with it and I'm not really sure if that even could help in this.