SAP Alert Notification service against multiple subaccounts

Is it possible for an instance of Alert Notification services to automatically consume events generated in other sub accounts? We have 2 global accounts - one for Integration Suite services that we purchased and another that is setup for CPEA where we will be running Workflow and some additional services.

Can one instance of Alert Notification be connected to multiple sub accounts and automatically process events from all connected sub accounts or do we need to subscribe to alert notification in each subaccount.