Alerts using Per_Periods_of_Service

Summary:

Can Alerts reference fields from the Per_Periods_of_Service table?

Content (required):

We need to automate an email that is sent to new hires after 90 days from their date of hire. Comparing the Per_Person.Start_Date with the Sysdate is not working as it's picking up a person's earlier pending worker record. i.e. the Alert run on 28-Sep returned two employees. One whose actual hire date is 28-Jun but also a pending worker record that was created on 28-Sep but whose hire date is 11-Jul. As the employment category is automatically created by the Taleo interface I cannot this to filter out the pending worker record.