Help with custom search/filter in wp-admin/users.php

Hi all;

I’m at a bit of a loss after searching hours on the internet all day today for a possible solution to what I thought would be an easy project.

I have created custom user roles on a website and removed the default ones (except administrator). With how I’ve customized the site, only the admin and the new user roles were needed (ex: user_level_01, user_level_02, user_level_03, user_level_04, user_level_05, etc.).

With this, I am aiming for a hierarchal search within the ‘wp-admin/users.php’ area based on user roles. I have been attempting to filter the search results to only populate users in certain roles (user_level_04, user_level_05). I don’t want the results to display higher-level roles (user_level_01, admin, etc.) – except obviously for the admin.

In addition, the role-selection area just under the ‘Users / Add New’ title within the page ‘wp-admin/users.php’ has predefined default populated roles (‘all | Administrator | Contributor | Editor | Author | Subscriber). I’d like them to be replaced with my lower-level custom user roles (user_level_04, user_level_05). The issue with that is that using FireBug, I cannot find where this function is so that I can edit, and I could edit the CSS style ‘.subsubsub’ to ‘display: none’, but then again, I don’t know where else it may be used and don’t want to risk hiding other features later on.

I’d prefer a functions.php solution vs. a plugin, but if the plugin doesn’t interfere with my current set-up, I can test it out and see if it works.

Thanks in advance for any guidance.