JSFiddle - React, Tailwind, and code Playground

HTML

<a class="fc-draggable" data-belongs="1" data-target="5">1 - 5</a>
<a class="fc-draggable" data-belongs="1" data-target="2">1 - 1</a>
<a class="fc-draggable" data-belongs="2" data-target="3">2 - 3</a>
<a class="fc-draggable" data-belongs="3" data-target="4">3 - 4</a>

JavaScript

$('[data-belongs]').not('[data-belongs="2"][data-target="3"]').hide();