Notifications and reminders for PMO and top management (stakeholders)

Hi! can anyone help me?

We need to organize a monitoring fore some kind of project tasks using notifications for PMO and top management on Project Server 2010.

For example we have an enterprise custom field that contains a mark about the task importance for top management. Requires that top management receive a reminders for  important tasks in this way:

• the week before important task start date
• three days before important task start date
• on important task start date

Is there a ways to achieve this goal? 

thnx for any idea!