JSFiddle - React, Tailwind, and code Playground

HTML

<div class="myTest">1</div>
<div class="myTest">2</div>
<div class="myTest">3</div>
<div class="myTest">4</div>
<div class="myTest">5</div>
<div class="myTest">6</div>
<div class="myTest">7</div>
<div class="myTest">8</div>
<div class="myTest">9</div>
<div class="myTest">10</div>
<div class="myTest">11</div>
<div class="myTest">12</div>
<div class="myTest">13</div>
<div class="myTest">14</div>
<div class="myTest">15</div>
<div class="myTest">16</div>
<div class="myTest">17</div>
<div class="myTest">18</div>

CSS

.holder{
  border:1px solid red;
}

JavaScript

var tmp = $();
$(".myTest").each(function(i){
  tmp = tmp.add(this);
  if(((i+1) % 5) == 0){ tmp.wrapAll("<div class='holder'>"); tmp = $(); }
});