Configuration Question

I am considering buying a Duo or Pro model ReadyNAS, but I want to ensure that it will work in my configuration. Currently I have an external hard drive connected to a Windows 2k3 server. That hard drive contains shared folders for the 30+ users that I support. There are various levels of sharing and security for each of the folders and sub folders. I have Symantec Backup Exec 10d on the server that backs up the files to another external drive connected to the server. I would like to migrate the shared folders to a NAS solution and cut the server out of the equation, but still be able to use Backup Exec to backup the files to the other external hard drive connected to the server. I also want to keep the current sharing and security permissions of the folders. I simply would like to know if this is possible with a ReadyNAS product. I apologize in advance for my ignorance.