Ubuntu / Apple :: Share The Same Shared Folder Between Multiple Users?

I'm using a Ubuntu Desktop 10.04 32-bit machine as my file server. It is sharing a few folders stored on a USB NTFS drive using Netatalk. The client machine is running MacOS 10.6.4. I have only one user on the Ubuntu machine, but the Mac machine has two users. I wish to share the same network share between the two Mac users, while both are logged in (they switch between one another without logging the other one out).

I created a login item on both Mac user accounts to automount the Ubuntu shared folder and used the same Ubuntu user account for authentication on both Mac accounts. This is the problem: When the first Mac user logs in, the shared folder automatically mounts with no problems. However, when the second user switches to their account (without logging out the first user) the automount mounts the folder with a red "No Access" sign on the folder. The only way to resolve it is to eject the mount and manually remount.

This is not the end of the world, but I would like to resolve this issue if possible, so that the users get a smoother experience. The way I tried to resolve this: I thought that maybe Netatalk does not allow the same user to connect more than once from the same IP, so I set up an additional user on the Ubuntu machine. when I connect to the Ubuntu server using the new user for authentication, the only share available for the user is their home folder. The other shares are not available.

I therefore tried to configure permissions using the AppleVolumes.default by explicitly giving all users the "allow" permission for all shares and restarting the Netatalk service, however the new user still has access to nothing but their home folder. How can I share the same shared folder between multiple users?