Yammer Networks

We have 6 domains/emails, which all set up separate Yammer networks and they need merging into one. Is there a simple way of doing this? I found the below article online but I am unsure on what will happen if I add a domain to Office 365.

https://support.office.com/en-gb/article/Add-your-users-and-domain-to-Office-365-6383f56d-3d09-4dcb-9b41-b5f5a5efd611 

Any help would be greatly appreciated.