Need help modifying the OG "add user" form to replace the user search box with first and last name searches I could really use some guidance with an OG related task. I'm needing to modify a form used to add existing users to organic groups. The path is "/group/node/1/admin/people/add-user". I need to remove the user search box and instead implement a couple of name searches: "Firstname, Lastname", and "Lastname, Firstname".  Not sure what I should be modifying via a hook_form_alter, or other hook. Any thoughts?

Attached is a before and after view of the form. I appreciate any guidance anyone can provide.

Thanks!
I ended up using a custom callback to populate a new field called "full_name", and then used JQuery to populate the username field on blur of my new field, and also hid the username field to make the interface a little more intuitive. It worked well enough, but it would be nice to completely override the submit function and use a custom one to ensure everything worked as expected. If a user enters in an invalid name and clicks enter, the default validation fires off, and nothing I've created works without a page reload. Kind of stinks, but at least it's working for the time being.