There's kind of a teeny tiny little Grand Canyon size gap in the idea to make an option to not allow people that are new, or even a set amount of clears.

"Selling Alex, Ravana EX, Bismarck EX!" etc groups exist. and while fairly overpriced, the people who have the gil and no skill are still going to find their way into your group by getting X amount of paid clears to bypass that check. You think that as soon as they become eligible for a run, they're going to pay whatever the price is now when they could just go leech off of your group for free?

Or on the other hand, they can start their own group requiring X amount of runs and hope they get the premium players so they can leech.