Need help on calc logic

Hi,

When I set a item as like item for two products, we throw a error. like item mapping should be unique. When I clear like item setup of one, error is calculated for first one (blanked out) and second one it remains as is though it is unique. We could see the error message is changing only if I update its related cell. How can we bring a dependency , if like item measure changed for product 1, it should calculate error for product 1 and product 2 or all products in workbook.

Example:

Step 1: Set like item for Item1, Item 2

               Like Item     Error message