JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.2/themes/ui-lightness/jquery-ui.css">
<dl>
    <dt>Items:</dt>
    <dd>
        <ul>
            <li>Item 1<div class="item-info">...</div></li>
            <li>Item 2<div class="item-info">...</div></li>
            <li>Item 3<div class="item-info">...</div></li>
        </ul>
        <ul>
            <li>Item 1<div class="item-info">...</div></li>
            <li>Item 2<div class="item-info">...</div></li>
            <li>Item 3<div class="item-info">...</div></li>
        </ul>
    </dd>
</dl>

JavaScript

function findCommon(selector) {
    var $items = $(selector);   
    var total = $items.length;      
    var parent;                   
    
    $items.first()
        .parents()
        .each(function() {
            if($(this).find(selector).length == total) {
                parent = this;
                return false;
            }
        });
    
    alert(parent.tagName);
}

findCommon('.item-info');