Allow access to a project depending on a project field or action in Sharepoint Workflow

(1) Is there a way to allow access to a project depending on a project field? (2) Alternatively, is it possible to automatically assign a resource to a project depending on a project field? (3) Alternatively, is there any action in Sharepoint Workflow that can modify the category composition? I would like to make the definition of a projects category depend on a project field, or that resources be assigned according to a project field to get the project into a category. I understand that a project can be manually added to a Category, but I would not want to give a large number of users permission to modify the definition of a category.