Remove endnote reference number from optical margin alignment

Hello everyone,

A document I'm working on includes lots of endnotes, which are up to three digits long. I've used optical margin alignment to keep the main text looking readable, but the endnote references are automatically included. The result is visually jarring when the endnote reference appears at the end of a line, as only some of the final digit in the endnote hangs over the margin. I'd prefer to keep the whole reference inside the margin. 

Does anyone happen to know if there's a way to specify this anywhere, or any kind of space I can add after the reference to trick InDeisgn into preventing the reference from crossing over the margin?

Thanks a lot!