Shadows and 3D objects

It seems I have a lot of questions, hehe. I am trying to figure out the best way to add shadows coming from other 3D objects in the scene, to the terrain. If I use the directional light, the terrain receives the lighting as well and it gets too bright. But I need the directional light in order to cast shadows from other meshes. I need this mainly for units, like soldiers or stuff like that.

Thanks!