Hi Emiliano

You might be able to do it this way.

Set up a site-wide role with the permissions you require. In our system Non-Editing Trainer might be what you want.

Then apply the role at the relevant category level. and then add the people to the role at that category. In the attached image we want two people to have editing rights in the courses inside this category. I think this method is considered 'old fashioned' but it works for us. The roles that can be assigned at the Category level are set in the Permissions at the site level.