The global notification settings on your BlackBerry device work like a master switch that either turns on or turns off the customized notifications that are currently set for apps or contacts. Customized contact notifications override customized app notifications. For example, if sound is turned off for the Phone app but is turned on in a customized notification for a contact, the phone still rings when the contact calls you.
If you want to customize how you receive priority messages in your BlackBerry Priority Hub, you can create a rule so that messages sent from specific accounts, with a specific subject, or with other criteria are sent to your BlackBerry Priority Hub. You can also turn on a Level 1 alert for specific messages so that you receive a custom notification for these messages.