Note: The question has now been reopened. I have added further examples of the group genitive to my answer to the question. This should help to distinguish it further from the hyphenated compound nouns question.
The following question
was closed as a duplicate of
The two question titles alone should be enough evidence that the questions are asking for different information. In the first, the OP is asking about the grammaticality of a possessive phrase ending with "me's" (The person behind me's...).
And in the second the OP is asking how to write the genitive form of hyphenated plural noun compounds such as passers-by and mothers-in-law.
The most highly upvoted answer in the "passers-by" question starts: "Mothers-in-law's" is a correct form. I am quoting the rule used in American grammar. And is simply followed by a blockquote of the rule whose first sentence is "Also add an apostrophe followed by an s to the end of a singular compound noun that ends in any letter except s". (No source for the rule is given.)
It is not clear to me how site visitors interested in reading an answer to the "The person behind me's..." question are helped by redirecting them to the only marginally duplicate "passers-by" question.