Hello, I need some help with a specific category permission. I have the following structure:

Category A
- Subcategory A
- Subcategory B
- Subcategory C

I would like to create users which will work with those permissions:

User A: Acess to publish and editing his own itens on Subcategory A;
User B: Acess to publish and editing his own itens on Subcategory B;
User C: Acess to publish and editing his own itens on Subcategory C;

The user A cannot access and edit user B and C content.
The user B cannot access and edit user A and C content.
The user C cannot access and edit user A and B content.

I know this is possible to make in K2, but I need to create and set a new user group to each user I create which is bad. Is there a extesion or someting which I can make this work easier? Because ill have more than 50 categories to set in this way.

You will have to Create a K2 user group per category you want your users to edit, i.e. User Group A which will include the filter for subcategory A, User Group B, which will include only the filter for subcategory B, etc.
Then all you have to do is assign each user to the correct user group.
I'm afraid there is no quicker way to handle this.

I see, I already have searched for some extension at extensions.joomla.org but I couldn't find it. The most closer i got was a memership component to access exclusive content, i need exclusive edition and posting in a easy way :P. I have founded this solution too by researching k2 component, but it will make me have lots of groups :/. Thanks for you reply Yiota, I will use this method until find something better.