attachment_fu & multiple directories

Hello,

I'm probably going to be using attachment_fu, but I need to have
groups of attachment repositories that are separate from one another,
but all within one rails app. My site will have groups of users that
will be allowed to share content and assets with each other, but there
will be many groups who should not have access or visibility to each
others' assets.

As far as I can tell, a given model class can only do
"has_attachments" when the class is loaded - and that is when the
storage location is set. There does not seem to be a way to specify at
runtime - so it can be different for different instances - where the
files will go. Can anyone confirm this? Or if I'm wrong, tell me how
to do it?

If it's not possible, I will probably end up modifying attachment_fu
to do it. If there's another attachment/file upload system that
already can do this, and that people would recommend, lay it on me.

Otherwise, I'm wondering if Rick Olson (the developer) monitors this
list, or if anyone can put me in touch with him? I'm hoping to get his
advice on the best way to add this functionality, and find out whether
or not he's interested in having it contributed back to the project.

Thanks,
Avram