# hairspace + hyphen as hyphen char with Fontspec

I would like to use for hyphen character the combination: hairspace + hyphen, in order to clearly but discreetly distinguish hyphenation from division.

The traditionnal way (using another character, like ≈) is not an option with the font I'm using, which have nothing that fits visualy for this use. I'm using Fontspec with Lualatex and have been able to change the hyphencharacter, but the documentation says

It takes three types of input, which are chosen according to some simple rules. If the input is the string None, then hyphenation is suppressed for this font. If the input is a single character, then this character is used. Finally, if the input is longer than a single character it must be the UTF-8 slot number of the hyphen character you desire.

Is there a way to use more than one char to define hyphen char?

1st edit:

Here's a MWE where I want the first hyphen (short-legged) unkerned, unlike the second one (in Supercalifragilisticexpialidocious):

\documentclass[a5paper,12pt]{article}
\usepackage{polyglossia}
\setmainlanguage{english}
\usepackage{filecontents,fontspec,microtype}
\begin{filecontents*}{garamond.fea}
languagesystem DFLT dflt;
languagesystem latn dflt;

feature kern {
pos hyphen' <500 0 0 0>;
} kern;
\end{filecontents*}
\setmainfont{Garamond}[
FeatureFile={garamond.fea}]
\frenchspacing

\begin{document}

\Large
The short-legged vulture is Supercalifragilisticexpialidocious.