That'd be a really cool feature to add, though.

I believe when you customize a race you can set their AI behavior; there is a generic AI, or there is one for each (pre-made) race. I think that the race specific AI's have these "grudges" coded into them, but I don't know of a way to isolate them and place them in other AI's, or a way to make a grudge against a custom race. You could give a custom race the Torian behavior and they would dislike the Drengin, but thats about the extent of it.

Alternatively, I think at the start of a game you can set the initial relations between races, however, this isn't as "permanent"; if you set two good races to dislike each other, they will still eventually build a friendly relationship due to their matching alignment.