Roles and permissions

Hi I have a problem with moodle I have five different course categories I have some course for each category.
I want that an user after login will be able to view only a specified category and he does't view the other.

I hidden all category and couses inside. For each category I have been created a specific role, inside the category contest I allow the specific role for the category to view hidden category and hidden couses.
This procedure doesn't work for category but it works for single couse. How I can solve this problem?
Thanks for your attention and for your time

best regards