Chat multisite setup for dashboard communication

Let me clarify what i wanna do:
- I have a multisite with subdomains setting.
- Each subsite has an author with "author" role.
- I want to create a chatbox which will appear only on dashboards of users.
- I will connect with them through this chatbox.

I couldnt achieve to do this. I can give you the pass for you to take a look at it.