How do I create a game available only for players above a certain level to join?

Games with no level requirement seem to have a big dropout problem-- half the players are replaced with AIs right away. A level requirement seems to help with that problem, but I don't see the option to require higher-level players in the "create game" process. Yes, I know the system creates some games that don't allow newbies, but I'm looking for country selection and no coalitions, so I need to create my own game and invite more experienced people to join.

Am I missing something in the create-your-own-game process?

Thanks!