Hi Fons.
That would be possible in principle, but it is a lot of work.
Would file-sharing of a folder be an alternative for you?
Do you want to see the name of the customer(s)? Then you would actually have to create a user and restrict the rights. This would also have to be done via a group with restricted rights because of the execution rights.
Are you a legacy user and have you installed the group administration?
Stefan