How to modify Chicago style to format footnotes - All authors first, then et al. for subsequent endnote of same citation

Hi all

I’m trying to create a modified Chicago output style using endnotes only. To repeat a citation with multiple authors more than once, I need the first citation to list all authors, and subsequent citations First Author, et al. for 3 or more authors.

I noticed in the Style Output editor that it can easily be done if I were using in-text citations; but I’m not. Using the footnotes feature only to produce endnotes.

No matter which options I change, it seems that I can only do one or the other: List all authors for subsequent citations, or use et al. for all citations, including the first.

Been struggling with this all day. I searched the archives and haven’t been able to find anything related to this sort of detail.