This is the screen I get for setting permissions. For my personal calendar(s) I am able to set permissions for specific people as your instructions describe, but for this one it is not an option. Only difference is that I created the calendar "From URL" instead of the "New Calendar". It looks like I can create a personal calendar and import the AirBnB into it as seperate editable events (which should then work as you described)- but it looks like I would need to do the import routinely to keep it up to date. Will explore if the original airBnB ical source works any better.