Sorting an attribute that is string ending in a number

Lets see the index is full of objects with just one attribute.

Search string is AC-2

Hits are:

AC-24.2
AC-21.2
AC-2.9
...
AC-2
...
AC-25
AC-24.1
AC-24

How do I configure it so the exact match of AC-2 is sorted above all else?