Updatable BAQ Question

I am creating an updatable BAQ that displays all operations that do not have a scheduling resource so someone can go and update this. I am trying to give the user a dropdown for the resource as it is related to a resource group. I see under Update -> General Properties there is a button called Advanced Column Editor Configuration where you can make the field a dropdown. This is where I get confused on how to filter out what is going to be in this dropdown. You can select BAQ as the 'datasource' for the dropdown, but this doesnt really offer any filtering option for the current updatable BAQ. I created a BAQ to display the resource, but when I test this in a dashboard the dropdown has every resource in the drop down and is not filtering out per row. Am I missing something? Have not tried one of these before.