Automatically select category “X” when user is “Author”

You can look at some of the membership plugins to limit access to the three categories. It would be difficult to write a program that would auto select categories based on post. It would most likely have to use AI to determine what post it belongs to.

However, You could create custom post types and have the user select the post type that best fits. You would then have to limit the users to the new post types.

Sorry @mrtom414 i think you have misunderstood what I’m wanting to achieve.

If the user logging in is an “author” I want them to ONLY be able to post to one of the three categories, and/or have that option automatically selected when the user goes to create a post.

@sc00t I think that would require custom code to achieve this, not sure if any plugin provides such function.

To limit the abilities of a user group you will need to assign Roles to that group. Roles are how WordPress defines permissions. If you want to limit what a user or group of users do you need to specify this with a role. There no magically formula that going to figure this out for you. You just need to find a plugin for assigning the roles you want.

To automatically select a category for each user you would have to determine what criteria too use to select the default category. In WordPress Categories and Tags are known as taxonomy. There is nothing in WordPress that will select a starting taxonomy based on a given set of criteria. You can search the plugins to see if you can find one. WordPress doesn’t possess any form of AI. It not going to figure out what you want .

You can limit what a user can do by using Roles. You can’t have WordPress decide on a given taxonomy based on some unknown criteria.