Blender's "smoothing groups" solution (Edge Split) destroys topology. Is there an alternative solution? I was searching for how to create smoothing groups in Blender, and everybody seems to say I should use Edge Split. But this will actually create new edges, destroying the topology of the object! Is the situation really so that I cannot create 'smoothing groups' without modifying the actual topology of the object? It will be very difficult creating models for game engines or exporting to other 3d software without smoothing groups, and I don't want to destroy the topology to achieve it either..

Here, I start with a smoothed sphere:



I then apply edge split on a face, as is recommended as blender's method of doing smoothing groups:



This is the result. Looking good so far...:



Then I try to select an edge loop here, but it stops on the affected area!



When I try to move one of the edges, the reason becomes clear: Two edges have been created, completely destroying the object's topology:
I suggest you use the modifier Edge Split instead.
In Edit mode, select your edges desired to be sharp. Hit Ctrl+E to bring up the Edges menu. Select Mark Sharp. Now add the Edge Split modifier.



Edges are split by the modifier. In Edit mode they are marked cyan. Topology is still fine: