I think I follow what you thought you meant to try to say. I had to read it a few times but now it makes sense. That's probably me more than you.
One way chickens have learned to live together in flocks is that when there is a conflict, the weaker runs away from the stronger or just avoids them to start with. I don’t know how big your pens are but size of the pens will have a lot to do with your success.
When two or more roosters are raised together, they often get along pretty well. When they hit puberty and beyond, they will decide which one is dominant. This may go so peacefully that you don’t even see a skirmish. It may be a fight to the death. Again pen size has something to do with this. If the loser of the skirmish does not have enough room to run away or avoid the winner, it is more likely to be a fight to the death.
That 6 to 8 week age difference is enough to make a difference. More mature chickens will dominate immature chickens. Sometimes they can be real brutes and bullies about it. But flocks have consisted of chicks and chickens of all ages for thousands of years. What I have in my flock right now would really freak out a lot of people, yet I consider it normal and natural. I have a mature dominant rooster, some mature hens, some pullets just coming into lay, some 7 week olds that a broody weaned a couple of weeks ago, and a broody with two week old chicks. Those are all roaming together without a real problem. When a 7 week old invades the personal space of a more mature hen or pullet, it might get pecked and run away, but usually the older ones just ignore it. But I have a lot of space. They can run away and avoid to their hearts content. If I were trying to shoehorn them into the tiniest space possible, I’m sure I’d have serious problems. I don’t know how much space you have in your pens. That is a huge concern.
Your general plan is a good one. Keep the younger six together and house the older next to them. Put the older in with the younger, either in the younger one’s territory or at a neutral site to avoid territorialism. The older ones being territorial is what I’d be concerned about. The less space you have the older the young ones need to be before you try this, maybe even waiting until the younger ones are laying.
People do this type of stuff all the time. Most of the time they are successful. But occasionally it ends in disaster. Good luck!
