You can create notifications that only trigger for changes on one item.
Adding specific item notifications
To create a single-item notification, select the item and in the Notifications pane in the Details Panel, click the plus icon.
Add any of the conditions you would want to trigger the notification and include any recipients, and click Save. If you want to notify customers of specific values (like when the workflow step has been changed to Fixed) you can select the option under When will this Notification run? and select the option for When specific field values are updated.
Tip: If your customer contacts are using the customer portal, single-item notifications are created automatically if you allow customers to the check the Notify Me of changes to this item box.
You can remove this permission by navigating to Tools Customer Portal Settings and reviewing your notification settings in the General settings section.