There needs to be a formal agreement among all G5s that an individual conference gets the bid and that all G5s can earn their way into that conference based on objective measures.
And if they really wanted to double down, the entirety of the CFP money allotted to G5s would go to the members of that conference. If all of the sudden there was a 6th conference with an auto bid and substantial CFP money, a substantially more lucrative TV deal would follow because that conference has relevance.