Suppress notifications from delegated mailbox

Is it possible to suppress new mail notifications from a delegated mailbox? Or is this not currently supported?

The scenario is with exchange (Office 365).

Office 365 user [email protected] has access to a delegated mailbox called Support Mailbox

When a new message comes into the Support Mailbox, the new mail icon appears on the Em Client icon… I’d like to disable this so that I’m only notified of new mail that is sent directly to [email protected] (I don’t want notifications for mails coming into the delegated Support Mailbox).

I’m aware that you can go to Settings | Notifications and click the “Default Settings” dropdown to configure notifications per account… however, this doesn’t work in this case, because the support mailbox isn’t a separate account (it’s delegated mailbox under [email protected]’s account), so it doesn’t show as an option in the dropdown.