DateTime offset from column on other table

I have two tables with a many-to-many foreign key relationship: 
campaign table with campaign_id INT and added_on DATETIME
status table with status_id INT and description VARCHAR
campaign_status with campaign_id INT, status_id INT, added_on DATETIME.

I want the campaign_status.added_on field to always be greater than the associated campaign.added_on field.  Is this possible?