How to set different folders for different manufactures?

I have version 1.39h of Zencart installed and am using the free template Flowers (Orange). So far so good getting things set up. My site is http://www.vividtovintage.com

Our store is goint to sell nothing but digital downloadable products. I would like to know how to add separate folders for each manufacture to be able for them to upload their zip files. Any help would be appreciated. I also need to know where to place said folders.

Thank you so much in advance!

Different folders will require some custom code

Letting others have direct access I view as an issue
As you will have to add the file name to the item anyway just give each an FTP area

That is what I am wanting to do. I want to have a separate ftp for each new designer and them to have their own ftp directory to upload into. I am sorry if i didn't make myself clear about it. I need to know how to if I need to set up any special folders or what?

I want to have a separate ftp for each new designer and them to have their own ftp directory to upload into.....
I need to know how to if I need to set up any special folders or what?
As I stated, they can not make these active for downloading without additional access to the admin

So doing what you stated is not a ZenCart issue
It is something that can be setup with most hosting accounts