It's been a good while since I last played about with ratings, but macguba is right...
I think there are functions relating to rank and courage in the game engine but they still have that "advanced designer" switch on...
At least in the config.cpp you can see that the rank Colonel has a numeric value of 7500 and colonels courage is 0.90...
It also seems that the basic ratings of all units are hardcoded as I can't find any mention of 'rating' in the config...
By far your best bet is a minor rethink on how the cutscene starts: if necessary just fake it, the player doesn't know who the highest ranking enemy left alive is anyway.
Quite.
If I remember correctly, CWC campaign is full of this...