Uploading file from within iOS app to other Dropbox account

Hi - I'm developing an iOS app where I want to upload a video directly to a "foreign" Dropbox account. One requirement is that the app user shouldn't need to have a Dropbox account. The app user presses an Upload button and the app will take care of uploading the video to the foreign dropbox. The user should then get a some kind of notification once the upload is complete. I've looked thru the documentation without identifying this use case. It appears that the user must either have a Dropbox account or the "foreign" account must make a request for files.

Any help appreciated.

/Micke