Global Tenant for Multi-Tenant Account

Customer needs to allow staff members to be members of all Apps and not have to log in and out with different UIDs for each one. Staff will need to provide support to all the tenancies, so need to be accessible to users in all tenancies in a scaleable way. Staff should be able to log in to their own account, and then maybe have a drop down of all the Apps to choose from or some way of navigating between the Apps without logging in and out and then be able to chat to users in those Apps.