How do I initialise a TEX2DARRAY in shader with RenderTextures from C# script

I am having trouble passing my Render Textures from C# script to a 2DArray in my cg shader for post processing effects.

While I have managed to initialise the Array with one Render Texture, I have not managed to get multiple textures into the array. I did that like this:

 Shader.SetGlobalTexture("_TextureArray", renderTexArr[0]);

I could then use the following commands to use the render texture in the shader:

 UNITY_DECLARE_TEX2DARRAY(_TextureArray);
 UNITY_SAMPLE_TEX2DARRAY(_TextureArray, float3(i.uv, index));

But how do I assign all elements of the array?