General :: Remove Permissions From Ext3?

I use an external hard drive for storing lots of files I share with friends and family.

I know I can set 666, but I can only do this in contained files and directories, NOT on the actual disk root. This means people can't write to the disk root.

Also, setting 666 might cause some issues when someone else pastes files and applies some other permissions.

Is there some way to remove permissions completely from an ext3 filesystem? I mean, have the entire "permissions" layer removed? Otherwise, what can I do?

Changing fstab is out of the question, this is a shared EXTERNAL disk; people use it on their computers, I can't go around changing their fstab.
The same goes to mount parameters.

[edit] Ok, I said ext3, but it's actually ext4. I don't see any difference in this case anyway, but just in case.