Within the post section of my website, I have 4 columns with varying heights based on their contents using Bootstrap 4 grid system. As shown in the image below https://i.sstatic.net/ZHHqR.png
When I resize the 4th column it rearranges.
https://i.sstatic.net/8Dp52.png
As seen in the image above, the 4th column shifts under number 1 but aligns based on the height of the 3rd column. I want it to stack like the photo below.
https://i.sstatic.net/0JPpE.png
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet"/>
<div class="row pt-3 port-folio-margins pb-5 pr-4 pl-4">
<div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 pl-1 pr-1 ">
<div class="post-container">
<div class="post-image"> </div>
<div class="post-title">TEST2016</div>
<div class="post-share-icons"></div>
</div>
<div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 pl-1 pr-1 ">
<div class="post-container">
<div class="post-image"> </div>
<div class="post-title">TEST2016</div>
<div class="post-share-icons"></div>
</div>
<div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 pl-1 pr-1 ">
<div class="post-container">
<div class="post-image"> </div>
<div class="post-title">TEST2016</div>
<div class="post-share-icons"></div>
</div>
<div class="col-xs-12 col-sm-6 col-md-4 col-lg-3 pl-1 pr-1 ">
<div class="post-container">
<div class="post-image"> </div>
<div class="post-title">TEST2016</div>
<div class="post-share-icons"></div>
</div>
</div>
So the question is how to achieve that CSS formatting with or without Bootstrap. I have tried using "float" with "flex wrap" and also "clearfix" without success.