alternative to single.php

Hi,

I’ve created a portfolio plugin which creates a page that displays an image gallery of custom posts. Each image in the gallery is the featured image of the custom post in the portfolio. When you click an image in the gallery you are sent to a post page that displays the content of the custom post. The content of this custom post are displayed on single.php. My question is, how do I get these custom posts to use a different template than single.php?

Thank you