Auto tag from predefined list

I’m aggregating posts using the FeedWordPress plugin.

I have a list of pre-defined terms that I’d like to tag the aggregated posts with. I’ve looked at a couple of tagging plugins; Auto Tag, Simple Tags, Strictly Auto Tags.

They’re good, but they are searching and making educated guesses on tags purely from the post content. Is there a plugin or a coding option that would allow me to auto tag posts based on a pre-defined list of words/phrases?

Thanks