How to add the "Select all" checkbox onto a "Select Page" with a list view?

I have a pair of entities and a reference set between them and I generated overview pages for the entities. Also, on the generated Select Page I replaced the Data Grid with a List View to have implicit checkboxes. Now I want to add the “Select All” checkbox on the top of the page. I wanted to add a regular checbox and attach an On Change Microflow to it and that microflow would clear or populate the reference set of the parent object and refresh the client. However, the problem is there’s no parent entity in the context of the page. In Mendix a Select Page does not need a page parameter. The currently associated list view items or the data grid rows are highlighted by some poorly documented part of the UI framework.