Access, notifications based on 2 different due dates

Hi, I am very new to Access and I am trying to design notifications based on 2 different due dates (Yearly & Semi-yearly). The document is the same for each employee, but some employees are due every 6 months and some every 12. I have found a way in a query to do either the 6 month notice, or the 12 month, but not both. Is this even possible? Or do I somehow need to set up my table differently?