I have some grass with several flowers sticking out of it. Grass and flowers are meshes with PNG images with transparent background. Alpha channel is set up properly, textures are perfectly see-through where they need to be. For reasons, I need to render the grass separately, and have the parts where the texture of the flowers overlay it masked out. I'm using Blender Internal (2.79 version still). Have tried setting up Mask Layers in Render Scene tab, as well as changing the flowers' material to Mask Transparency, but as expected both times the whole mesh is used as a mask. Is it possible to set up the flowers' texture in a way where PNG's transparent pixels would remain see-through, and opaque pixels would be used as a mask?