Here is how you can restrict users from selling specific category of products
Works only in version 4.0 onwards.

Administration Menu > Maintenance > Resources
To restrict specific product categories from users, add below lines in user role.

<class name="category.breakfast"/>
<class name="category.lunch"/>
<class name="category.dinner"/>

Here the user in this particular role can only sell products from categories Breakfast, Lunch and Dinner.