Hi Alex,
I would suggest to create two entities actually. You can then associate name with car (1-*). Behind the save button, you should have a microflow that sets the association between Name and the selected cars. Also good to mention: think about the UX/UI aspect of your page. Is this the most convenient way of letting the user select a name and associated cars? You can also decide to use a datagrid on a page with all the available names and a button that brings the user to a pop-up page. This pop-up page then shows a listview/datagrid of all cars that the user can (multi) select. Don't forget the microflow at the end that sets the association between (list of) cars and Name :-).
Hope this helps Alex, and good luck with your project!