In a quick test, where my citations were inserted from endnote and then I followed the instructions here: https://www.dummies.com/software/microsoft-office/word/how-to-create-a-table-of-authorities-in-word-2013/ I was able to mark endnote citations using the Word tool in a test document and insert the “index-like” table of Authorities. Since my paper wasn’t a law like document, I wasn’t really able to see if that worked as it should though.