Can I copy index entries from one InDesign document into another?

I'm preparing two books that will have a lot of index entries in common. Is there a way to load all of the index data from the first into the second, and have it go find all of those words? I am formatting the entries in the first to "add all", and I need that to happen in the second when I bring in the entries. "Import topics" is in the pull-down menu in the index panel as an option, but I am entering these items as "references".