Daedalus01 is correct. There is no re-open notification setting, and it falls under New Message Alert.
What you can do as a work around (note: I do this) is that the Department managers are "fake" accounts, and the email for the account is actually a mailing list for the Department. So when the Department Manager gets notified for anything the whole team does.
example:
The billing department manager account is name: "Billing Department", with an email address of "billing@domain.tld". I use a password generator and make a super long complex password and set the password on the account.
