Securing shares

I have a share called “home-rooms”created in windows 2003 server. Inside the share i have some folders ,i.e. room 412,room 500
etc.My problem is I have kids that can get to the share ,but they can drag-n-drop the homeroom folders into the other folders. I have played with the folder permissions. And cannot get the security i need. i just need for them to be able to create their docs,and modify. And restrict them from deleting the folders,and drag-and dropping into different folders. Thanks in advance…