QlikMaps 2.1 introduced true multilayer support, with multiple layers displayed on a map at once. To do this, you'll use an expression similar to:

=IF(COUNT(DISTINCT TOTAL YourValue) < 500, 'ObjectID', '') 

Note: This example uses a Polygon object for the high-level view and adds a Points object for the detailed view, but you can use any combination of Points/Polygon objects in your Multilayer object.

At a higher-level view, the Polygon object is visible.

When the condition set in the Points Layer expression is reached, the Points object is visible.

Note: The layer control in the top-left allows you to control which layers are visible on the map. Simply checking and unchecking the box will show and hide the selected layer.