Manage Separate User FTP

Here’s the scenario… I have a fully hosted domain ( owned by User1. I have a php script on this domain that saves uploaded files. I would like to permit a partner of mine to access the uploaded files via FTP but I don’t want them to have access to the other directories.

I tried creating another user and remapping a directory per the knowledge base (, but the new directory is owned by User2 and as a result my php scripts that run under User1 cannot write to the directory owned by User2.

Does this make sense? I there any combination of users, groups, subdomains, etc. that would permit this scenario?

Thanks so much.