How to allow users to create categories only for their own blog ?

Hello,

Is it possible to allow users to create categories only selectable by themselves (in article create form) ?

I mean :
i have several "public" categories that i can restrict the use by ACL ...
I want to allow users to have their own categories but only usable by themselves in their own blog

user 1 have a "cars blog" and categories : audi, hunday...
and user 2 have a "travel blog" and categories like : asia, europe...
ans so on...
users don't need to see categories from others...
and i don't want the list of all categories in the categories page... only the public one is enough

Is it possible ? and how ?

thanks
loïc