Custom Binding Classes

Hi,

I have created a custom module called "Company" where I can add companies to a Custom table. I have followed the "Creating custom binding classes" documentation to create a binding class which allow me to assign users (Admin Users tab) to the created companies. In the "Admin Users Tab", I can click on the "Add items" and the site shows me a list with all the users that I can select. Is there any way I can filter the user list to only show the users that are not already assigned to a company?

Thanks.