Is it only possible to add a gallery to a menu? I can't figure out how to add it to a section or category... Is this not possible? Is this not violating "the way to add content" in Joomla? (Yes I'm a newbee in this world...)

I'm trying to add a menu link to my gallery that is only for registred users... The only place to set this is when creating a new gallery menu item... Then the link is not visible until a user logs in... I want to show all menu items and when a not logged in user clicks the link a restricted info page is shown (as in normal Jommla articles that is added to some category...)