Blending 2 Terrains Together

Hello,

In my game, I want to have 2 terrain objects, and at times, have the second terrain object being slightly above the first. The issue I'm running into is that with a directional light set to shine directly down, a shadow area appears around the entire border, like shown in image1. This is obviously due to the inclination of the second terrain on the border. My question is whether I can use shaders to eliminate this effect. I have already downloaded the unity terrain standard shaders, but I would greatly appreciate some pointers as to what I should look to change in order to achieve something like image2 around the entire border. (image2 was done by setting an inclination to the directional light, but that causes more shadows on the opposite side as it should.) (For game purposes I do need them to be 2 different terrains rather that just having 1 terrain)

Thanks for any tips!