Sorting references into groups based on Word list

I have a list of about 700 references in Word, and I need to search for each one within a single EndNote library to sort it into one of 15 groups. If anyone knows a relatively painless way to do this, help would be greatly appreciated. Otherwise Ctrl+F for each one seems to be the only option. A few references (55) fall into more than one group, but I guess sorting those could be done manually if there’s no other way. Thanks for any help.