I'll pass along the feature request.
In the meantime, you can add your own buttons for email, Whatsapp, or other social media sites and use a link generator such as http://www.sharelinkgenerator.com/ or https://sharethis.com/social-media-buttons/ to create the link for you. Here's more info:
How to add buttons in InDesign (not PDF) that shares to social media and email?
If you'd like to share a specific page using in5's built-in sharing buttons, you can export with the Output set to Multi-page web. Then in5 will add the URL using the numbered page to the share button.