As long as you wrap your buttons in the macro condition checking the parent, I can't see why that wouldn't work. Although, off the top of my head, Im not sure if there is a condition for checking if a user is authorized for a node. All I see in the current user macro for permissions is authorized per resource, and authorized per ui element. Not sure how your pages are all set up, so maybe one of those could work, but worst case, you can create a custom macro that will return exactly what you need, and use that to determine if the buttons should show or not. If you don't want to do that, then maybe you can figure out a way to use the memberships if they aren't already used for something. There are macros that are built in for checking the current users membership. Just a thought.