Ask HN: Manage multiple email mailboxes in a single dashboard?

There might be a really obvious answer or simple solution to this, but would love any feedback either way.<p>I'm running something similar to an agency model with multiple clients and need to manage emails to a specific mailbox on each client's behalf. e.g client1@myagency.com , client2@myagency.com.<p>I need to give shared access to both the client and my agency but mostly the mailbox needs to be managed and monitored by my staff/agency.<p>I need to be able to setup accounts super quick and be able to get access to ALL mailboxes from a single dashboard, while allowing the client access to their own mailbox outside of the dashboard.<p>Any suggestions anyone?