Identifying if a list item is a property on a separate list
I have two numbered lists, City and Product.
Product has City as a property.
All Products have a City as a property, and multiple Products can have the same City as a property, but not all Cities may be linked with a Product.
In a module with City list as a dimension, how could I identify if a City has been linked with a Product (it doesn't matter if it's one or many)?