Agent List in Drop Down - Alphabetical?

Summary

Can the drop down order be changed?

Content

When an incident is assigned to an agent, what drives the order that the names appear in the drop down list?

Most other drop downs i can control the order with how they are entered in the system.  (Products, queues, etc.)   But the agents seem to be a little different.

We do have our agents organized by groups, but i don't see any way to control the order of them in the drop down windows. 

Am I missing something?

-Dave