Attachment Security Modification?
 

I need to provide a small file modification service and I hope to use the attachments in a sub-forum for this. The idea is for ANY user to create a thread and post a file that only a specified user(s) will be able to access. They will then post a reply with a modified file and I need the thread creator to be able to download the attachment, but ONLY for that thread, so I do not want to add them to the group that can download from that forum.

A bonus would be if the thread creator or moderator could somehow add other users as co-owners so they could also get the download (but only once they had special permission). All of this of course should happen without the need to use the back-end ;-)

Is this sort of thing possible? Does it need a modification? Any ideas appreciated.

Anyone?

There is (used to be?) a mod that would allow the poster to specify who sees the thread, so you might want to start with that one and see if you can modify it to fit your needs.