When a member closes all 14 numbers, the leaderboard will indicate the date on which he or she finished, and the leaderboard will be sorted accordingly. That way, you can continue the pool until a certain number of people have finished.

Also, your pool can be reset anytime after the first member completes their grid, so you can restart your pool again in the same season. When resetting your pool, administrators can keep the existing pro team assignments or change them as they like. (Note: Pool resets require a re-payment of the pool fee.)