Yes that would work. It would require extra user setup to indicate which meshes to light together, and could hurt build times (if you merge everything together), but at least you would have control over the lighting seams, right? BSP actually does this already for co-planar surfaces. Static meshes can be anything so we can’t automatically merge it.
There are some other approaches to this problem that don’t require artist setup but so far none of them seem feasible.