The short answer to your question is - Sure!
If you have the right editing tools, and know how to use them, you can change anything.
This is a game, after all, governed by a bunch of zeros and ones in your computer's memory.
But, why bother?
The AI Lords lead troops trained to use formations, and have a cadre of officers and noncoms to help keep them in formation.
The parties you are talking about do not.
[Well, Patrols and Deserters, maybe ... but they lack the cadre and discipline to maintain any organized formation.]
They are rabble, and should behave like rabble. Which they currently do.
I cannot help you to achieve your stated or implied goals.
It would be ... historically inaccurate.
Please try to enjoy the mod as is.
DARoot