Wordpress custom sub template, Template within template
<p>I have a custom post type defined in Wordpress. Please look at the following image(not my work just used for reference):</p>

<p><a href="https://i.stack.imgur.com/DHGYS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DHGYS.png" alt="enter image description here"></a></p>

<p>For each of the posts within the custom post type I would like to define 3 sub templates that can be chosen from within the WP admin:- Content left, Content centre, Content right. When they are rendered out within the loop (not single page) the output would be similar to the above image.</p>

<p>Can this be done in Wordpress? If it can please can you help point me in the right direction?</p>

<p>Many thanks in advance.</p>