impersonate (only display mailbox data such as number of unread items, calendar)

Hi All ,

I have one task with our Application team they request from me to create a new service account and make  impersonate to all mailboxes in our exchange 2013 .

i want to gave them only display mailbox data such as number of unread items, calendar and No access to full Mailbox User.

How i can do that ?

Thank You .