You can access directly from HTL
SCREENSHOT (with the name of the design multifield property I am trying to access) :

CODE:
<div class="container">
<sly
data-sly-test="${currentStyle}"
data-sly-use.xtcontainerstyleResource="${currentStyle.path}">
<div data-sly-test="${xtcontainerstyleResource}" class="${currentStyle.containerCSSClasses}">
<sly data-sly-test="${xtcontainerstyleResource.hasChildren}"
data-sly-list="${xtcontainerstyleResource.listChildren}">
<sly data-sly-test="${item.name == 'divElements'}"
data-sly-list="${item.listChildren}">
<div class="${item.cssClass}">
<sly data-sly-resource="${ item.name @ resourceType='wcm/foundation/components/responsivegrid' }"></sly>
</div>
</sly>
</sly>
</div>
</sly>
<sly data-sly-test="${!currentStyle}">
<sly data-sly-resource="${ item.name @ resourceType='wcm/foundation/components/responsivegrid' }"></sly>
</div>