How can I write in the margin for a Script-like format?

[ChicSheik]

Hi!



I am trying to format a document for an opera libretto, and I want it to look like the attached picture example (screenshot from librettidopera.it, please excuse the fact that it is sideways). Essentially, I want the main body of the document to have the speaking parts and stage directions, and the margin to have the names of the the ones speaking each line. I can't use columns because columns are continuous from one to the next, and I tried using a 2x1 table, but the more pages a table takes up, the less willing it is to format cooperatively. Text boxes do not line up the way that I want them to. Any suggestions? Thank you!