Prevent users from writing ads in the parent category.

Prevent users from writing ads in the parent category.

Hi!

I created a parent category: CatONE.
I created 3 daughter categories assigning each to a specific group of advertisers:
CatA --> UserA
CatB --> UserB
CatC --> UserC

Then UserA can place ads only in CatA
UserB can place ads only in CatB
UserC can place ads only in CatC

But I have a problem: all users can place ads in CatONe. How can I avoid this?

I tried to set the Super User as the only CatONE advertiser. But this makes it so that the other Users can not create any ads.

How can I fix it?

Thank you!