The acceleration structure builder is selected automatically in OptiX 7 and will use splitting by default, but there is an OptixGeometryFlags named OPTIX_GEOMETRY_FLAG_REQUIRE_SINGLE_ANYHIT_CALL with which you can disable that exactly for such algorithms.
Related forum topic with links to the documentation and other cases.
Note the comment inside the OptiX Programming Guide saying that this may affect traversal performance.
https://forums.developer.nvidia.com/t/anyhit-program-as-shadow-ray-with-optix-7-2/181312/6