Light betwen multiple StaticMeshes

I don’t know why… but here is my problem…

At this edge, two static meshes are touching each other perfectly. They were created with 3ds max and the lightmap is auto created with “Unwrap UVW” For the light, I use a Directional Light as a low soft environment light and at the right side a lot of static point lights. How can I “share the light” between this two static meshes?


And yes… I know about the faces which normals are showing in the opposite direction to the viewport.