Would it be possible to create logic in the shopping cart that excludes the purchase of certain items if a family has a conflicting item in their cart. For example, we are using the shopping cart to allow parents to sign up for summer sessions. Currently, parents can sign up their child for multiple sessions that occur at the same time even though that child cannot attend all the sessions. What would be useful is if we can have something within the shopping cart fee that allows us to specify items that cannot be purchased if an item is added to the cart for a specific student.