[jitter] Layering multiple textured planes

Hi,

I'm creating textures using gl.sketch's @capture attribute and loading them onto planes made using gl.gridshape. The textures I am  making are mostly blank with a few lines drawn on them. I need to layer a bunch of these textures on top of each other. Can I make the blank areas of the textures transparent and then render them onto transparent planes made using gl.gridshape? If not, what else can I do to achieve this effect?