Change category order in People Picker

We've added a custom claims provider called "External Users" and it is showing above internal users. This is not acceptable to the users who will be using People Picker.

Before the custom provider was installed, users would see:

All Users
Active Directory
Organizations

After the cutom provider was installed, now they see:

All Users
External Users
Active Directory
Organizations

This seems very counter-intuitive to the users. They will be dealing with INTERNAL users far more frequently, with an occasional need to add external ones. Having external users appear first, categorically, is being frowned upon by our users.

Is there any way to change the category order in People Picker without needing to re-write a custom People Picker? Is this something that's a quick, easy fix or is it something that requires extensive coding?