Routing armies and friendly fire

[onomastikon]

Do you think it would be possible (or rather: not too difficult to implement) to either make it an automatic default or a check-box you can click in the "set battle orders" part to not attack routing squadrons and / or routing armies?

I mean, if you see they are routing, it is often not only better but perhaps ethically sensible to not slaughter them.

Well I'll stick to the "better" (functionally).

- If squadrons are routing but the entire army isnt, it would make more sense to concentrate on the enemy that is still there.
- If the entire army is routing and they are Independents, they have no where to flee and hence are no worry anymore. Why attack?
- If the entire army is routing and they are an enemy nation, it might make sense to attack so that no one survives, but could often involve heavy losses through friendly fire. It would be interesting to be able to toggle "attack routing units" here on and off.

What do you think? Desirable and doable (without too much resources for the developers)?