[horde] If using IMP authentication, how do you perform groups and user security

[Taylor Dondich]

I am attempting to use Horde/Imp/and Gollem for example for doing a 
groupware solution.  I want the user to login once only and using IMP's 
authentication is the easiest; however, in Gollem, I want users to be 
able to upload files and have other people who are in their department 
to access their files but no others.  I don't know if this is possible 
because without doing horde authentication, you can't create groups and 
such.  I am using the VFS, so there's no server level security in place. 
 Does anyone have a solution for this?

Taylor Dondich