Chat Plugin One-to-One Feature?

How do you enable/use the one-to-one chat function?

I want to use the WPMUDev Chat plugin on my client's site so that logged in users (employees) can answer presales questions from customers (public) via chat messages. After testing, however, it seems that this plugin is only for a site-wide chat that everyone can see, which doesn't help me since all site visitors can see the ongoing chat upon logging in.

I have seen in a couple of places (WMPUDev blog & the plugin description pages) that one-to-one chat is a features of this plugin, but there doesn't seem to be an intuitive way to access that feature in the settings. Am I missing something?