This is a common mistake. A 'share' is merely a name/shortcut to a directory. when you create a share, you have to point it to the directory you actually want it to be.
lets say you have /mnt/tank as your volume
you create share called music and one called documents
you would need to create either a dataset within /mnt/tank volume, or create a folder within that volume called music and one called documents. if you set music and documents to point to /mnt/tank, you are doing nothing but sharing one folder with many names.
use datasets, it will make your life easier.
configure dataset on your volume
share out that dataset
rinse, repeat