Thanks for your answer,
the problem with your solution is to involve persons with no real
understanding of webcontent and cms in processes and give them permissions.
I first thought about a php script, but there i have a problem with owncloud,
which is my preferred way to make things easy for that persons (networkdrive).
If I want to use your way, the only solution would be two upload formulars, which have to be on a secured page. Then there should be a php sript possible but this is not a very elegant way to do this. Also there must be few interrogations as the uploads are not done at a fixed time and sometimes there will be a few changes over a day.
Regards
Oliver