Civ 4 defensive combat change

Come to think of it, shouldn't it be possible to decide in advance of defensive combat who of your units should defend first? You don't want your elite units to take the first blows because they have a slight strength advantage when you know your units are inferior.

This could be accomplished by choosing between categories like: 1 always go first, 2 stay in the middle, 3 defend last.

I would like to hear what you who are more experienced in combat than me thinks...