I've working on a voxel like game like Minecraft, but I'm not sure how I should handle alpha. I've got the world split into chunks and I render each chunk, I have things like leaves which have alpha which is either on or off, but if you look through them you can only see other chunks which have already been rendered, here's a picture because I can't explain it.

https://i.sstatic.net/py0yz.png

It also works with leaves from the same chunk, for example if I'm looking through them from one direction to another then I can see the other leaves through the leaves, but if I'm looking the other way I get the same effect.