Keyword Grouping Tool?

Does anyone know of a tool that I can plug a huge list of 3-4 word keywords into and it will group them based on multiple common words in the keywords?
I don’t know if that made any sense, but:
Say I build my keyword list in excel using both manual methods and tools.
When I’m up to a few hundred to several thousand, I run it through a tool that gets rid of duplicates.
Now I’m left with a long list from all these different sources.

Randomly in the list, I end up have the following terms:
Cingular Ringtones
Free Cingular Ringtones
Cingular Realtone Ringtones
etc.
I would put those all in one adgroup, but what a task it would be to sift through thousands of keywords to make logical groupings like this.
Is there a keyword tool that will sort my list based on common words in each keyword?

Original post by Jondoe0069