windows 2008 r2 FTP and network access

I have two multifunctional devices so I setup my FTP server and add two virtual folders.

First multufunctional device have IP 192.168.0.10

and second multifunctional device have IP 192.168.0.11

So in FTP server I have locked virtual folder scanner1 to IP 192.168.0.10

and second virtual folder scanner2 to IP 192.168.0.11

Both folders are also shared folder so users can map that shares on their windows 7 clients and when scan some documents they can have acces to it by mapped disk.

Problem is because I need to lock those shared folders to only users which can access to scanner 2 shared folder.

When I set permission for that folder to only John and Mike and delete Users, multifunctional device can not access that folder scanner2.

So what I need to do, to lock that folder scanner2 to only those two users by network share and multifunctional device still can save scanned files to folder scanner2 via ftp.

I never left an open problem....I search, dig and ask, until it's solved....