I used the Bootstrap 4 buttons plugin (https://getbootstrap.com/docs/4.0/components/buttons/#button-plugin) and added the class rounded to the labels and the class mx-1 to the middle button to achieve the desired look and feel of separate radio buttons. Using the class btn-toolbar made the radio button circles appear for me which is not what I wanted. Hope this helps someone.
<div class="btn-group btn-group-toggle" data-toggle="buttons">
<label class="btn btn-secondary active rounded">
<input type="radio" name="options" id="option1" autocomplete="off" checked> Active
</label>
<label class="btn btn-secondary rounded mx-1">
<input type="radio" name="options" id="option2" autocomplete="off"> Radio
</label>
<label class="btn btn-secondary rounded">
<input type="radio" name="options" id="option3" autocomplete="off"> Radio
</label>
</div>