Manually load LODs for tiled landscapes

I have read this documentation for using LODs with world composition (World Composition User Guide | Unreal Engine Documentation). This mentions that it auto-discovers files with the formatting of “FILENAME_LOD#”. The problem is that it only auto-discovers other .UASSET files, I have a bunch of .r16 files, not .UASSET. What is the easiest way to convert a bunch of .r16 files into .UASSET files? What I can do is copy & paste an existing UASSET map, and rename it to have _LOD#, and that works, but it is the same file with the same detail. I’ve tried to right click → import my .r16, but it won’t import those. One thing that works is to import my LOD’d version of my tile as a tiled landscape, but then I have to rename it afterwards because of the naming style.

Question in short: How do I get .r16 files into UE4 for use as LODs without a bunch of renaming?