Hi Stephen, thanks for reaching out with your Q. Let me answer your Q with some details.
The US and EU infra allow customers in their regions to keep their data and configuration, separate. The logins for all our customers is central. So login once, and you can switch between the two different cloud hosted infrastructures (EU and US). The data and configuration in both sites is kept separate, so you cannot combine the two dashboards into a single dashboard. There are two ways that a customer can deploy their networks. If they want single dashboard to manage all their sites worldwide, then they can simply create all the venues under one hosted region. If they want to keep their EU sites hosted in EU region, then they can assign licenses during license activation to the EU region. Once those venues are set in EU region, they can only be managed by visiting the EU dashboard.
If you are a ruckus partner that manages customers in the separate hosting regions, then you would need to visit each site separately (you can login once, and then use links or URLs to switch between the two sites). Customers in each hosting region would be inviting you separately of course.
Just to re-iterate, the hosting sites do not share customer data or configurations. This is by design.