Hi,
3dgs automatic entity culling is made by the structure of the BSP tree (3dgsPro only) of the level. It can be fine tuned by regions. You can use regions with lower 3dgs licenses but the function that allows you to customly hide/show the content of a region is 3dgsPro only too since it is BSP tree structure dependant.

You can draw regions with lower 3dgs versions in WED and build a list of entities contained by each region after level load so you can manage their visibility by some events, proximity or so.

Salud!

edited: oh yes! culling by lod stages could be a solution too.