Capability for restricted access

Hello!

First of all: Thank you for that Plugin!

This is my problem:
When I upload a file as an Admin, I can set Users, Groups,… who would have access to the uploaded file.

As a non-Admin, esp. as Subscriber, I can upload a file, but not restrict access (I’ll be informed that I didn’t have the right to do that..).

I’ve tried to check capabilities, but didn’t find the one which rules the ability for restricted access.

Can anybody help? Thanks a lot!