Insert After

HTML

<div class="parent">
    <p>some text</p>
    <p>some text</p>
    <p>some text</p>
    <p>some text</p>
    <p>some text</p>
    <p>some text</p>
    <p>some text</p>
</div>

JavaScript

var elements = $('p:nth-child(5)').nextAll('p').detach();
var nextdiv = $("<div></div>).append(elements);
$('.parent').after(nextdiv);