Is there a way to make a distinction between TOC books and topics in HTML5 layout

We are using a customized version of one of the standard HTML5 layouts.

In WebHelp there was a different icon for books vs topics in the TOC. We found this helpful when you have many different levels in your TOC.

In HTML5 layout, there is no way to know if an entry in the TOC is a book or a single topic. You have to click it to find out.

Is there a way to do this in the HTML5 layout?

We are using RH 2017 on Windows 10.