Required Directories

[Grant Peel]

Hi all,

I have several servers that the users home directories contain directories 
that must exists in order for apache and mail to work correctly.

The users have full read write access to thier home directories via ftp. (I 
am using proftpd as the backend).

Is there a way (by using either proftpd, or setting sticky bit, or setting 
the uimmutable flag), that I can prevent the users from deleting these 
directories, and still retain the ability for my (root run) scripts to have 
the ability to delete them?

TIA,

-Grant