Hey,
thanks for the answer, but that is not what I mean.
There are about 40 users. User A, User B, User C, etc.
I did set up all galeries with the main admin account. Now I want to change authorship of every gallery to a different user each. Gallery A to user A, Gallery B to user B, etc. So when a user logs in, he should only be able to access his own gallery and make changes to it. So the standard WP user roles won′t help here. We did set up a website as a local business registry where every business has its own page. It already works in a way that a business logs in, then they can only see their own page and can also edit the site. Now they should be able to edit their own gallery only.
Hope I could make it more clear and you can help me.
Cheers,
Marvin