With all the staggered age groups, it will require some juggling. What you should have done, and make note to do in the future, is to have all of your chickens in proximity of one another so they can begin to get acquainted at the very start and used to the idea of being one flock. That means rigging a brooder in the coop or run so the one-week olds will start to integrate right away.
The four-week olds can start to mingle with the six-month olds right now using a panic room setup. Rig some chick size openings (multiple entrances) in their pen so they can return to it when they need a rest from the pecking order. This way, they can have a safe haven from bullying and injuries can be practically eliminated.
As your one-week olds become acquainted with the flock over the next two weeks, at their three-week mark, you can add little entrances to their brooding pen so they will also have a "panic room" to run to when bullied but can begin to mingle and learn their places in the pecking order.
Keep food and water in these safe pens so the small fry always have safe access to the essentials. By the time the two sets of youngsters are around three months old, the panic rooms can be done away with. At that time, as long as you have plenty of space and perches in the run at varying heights, the youngsters can have escapes that will assure they can evade bullying. But by that time, most of your flock will be a solid unit.
I describe the integration process in this article.
https://www.backyardchickens.com/ar...and-start-raising-your-chicks-outdoors.71995/