How do you filter by a Page Parameter and Listen to a Datagrid at the same time?

I can filter by a Page Parameter or Listen to a Datagrid but not both at once

I have a DataView that listens to a DataGrid. This part works well. I've added a ListView to show related records inside the DataView. This also works. What I need help with is adding an additional filter so that only items that match a Page Parameter are visible in the ListView. I haven't been able to figure out how to access a Page Parameter from within the XPath of the ListView. I've tried placing all of the above elements inside a DataView that takes an Entity (page parameter) as a Context but I don't know how to refer to the Page Parameter.

I'm also able to place my ListView directly in the DataView that accepts the Page Parameter and filter correctly, but then I can't access the GridView to have my ListView get filtered as the user clicks on the DataGrid.

Can you help?