Thanks, Varun Rathore
. It works perfectly!
For those who want graceful collapse from 4 items per row to 2 items per row depending on the screen width:
<ul class="list-group row">
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_1</li>
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_2</li>
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_3</li>
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_4</li>
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_5</li>
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_6</li>
<li class="list-group-item col-xs-6 col-sm-4 col-md-3">Cell_7</li>
</ul>