Shaderlab Multiple Texture Layers

Is it possible to have one texture appear in front of another and show the one in the back trough its alpha channel?

I already made it so i could use transparency. But i can't seem to find a way to put the other image in the transparent part. Also i'm making an unlit shader.

Here's my code:

     SetTexture[_Alpha1]
     {
         Combine texture
     }
     SetTexture[_Texture1]
     {
         Combine texture, previous * texture
     }

This handles the transparency.

Now how could i combine _Texture2 so it would appear in the back in the trasparent part?