Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)

On Error Resume Next
 ' use lower case for the address
 ' LCase converts all addresses in the To field to lower case
If StrComp((Item.SenderEmailAddress), "bad.email@gmail.com") Then
    Exit Sub
End If

        Prompt$ = "You sending this from " & Item.SenderEmailAddress & ". Are you sure you want to send it?"
       If MsgBox(Prompt$, vbYesNo + vbQuestion + vbMsgBoxSetForeground, "Check Address") = vbNo Then
         Cancel = True
       End If

End Sub

Private Sub Application_ItemSend(ByVal Item As Object, Cancel As Boolean)
    On Error Resume Next
   Select Case LCase(Item.To)
    Case "alias@domain.com", "alias2@domain3.com", "alias3@domain3.com"
        Item.Send
    Case Else
      Prompt$ = "You are not sending this to " & Item.To & ". Are you sure you want to send the Mail?"
       If MsgBox(Prompt$, vbYesNo + vbQuestion + vbMsgBoxSetForeground, "Check Address") = vbNo Then
         Cancel = True
       End If

    End Select

End Sub