Sharepoint list and calendar events

Hi All,

I have a sharepoint list with State, Brand, SubBrand and Recertification Date columns. 

I need to add the Recertification date to the Calendar. My requirements is I need to add only 1 event to the Calendar if the State and Brand are the same instead of adding event for each item. Is there a way to achieve that. Any help greatly appeciated.

Thanks

Prabha