Sorry if my requirement was not clear enough. so here's better explanation:

I have a group of users who needs to access their home directories that exist on a mounted drive called /new
so every one will have his home directory called "/new/user_name"

now they need to add files to their home directories but i don't want them to directly login to the UNIX box to add files, i want them to have only one way to add/write files to their home directories which is through FTP only