How does it work with public groups?

Is there any means of permission management in public groups?

I want to create a public group, but I want it all to organized and pretty. When someone joins do the mod still have to accept him? Also I would like to have a folder where only the mods and the admin could add files. There would also be another folder where averyone could place files. My Idea is to have "Buffer" forlder, and only after the file is checked to be good and organized (image, tags, etc) it would be added to the "real" folder.

Thanks anyway. And good luck with making wuala better.