You cannot house them together and feed them different things. That will not work. They all will eat the same thing.
I don't know what feeds are available in your area or in your feed store. I'm pretty limited in my choices. In general these feeds might be available to you. The percentages protein can vary a bit depending in brands and what they are actually called could be a bit different, but they should be close.
Starter - 22 to 24% protein
Grower - 16% protein
Developer - 15% protein
Combined Starter/Grower - 20% protein
Flock Raiser - 20% protein
Layer - 16% protein and high calcium content for egg shells
Stay away from Layer until they are all old enough to lay. The extra calcium can harm growing chicks. Once some get old enough to need it for the egg shells, just offer oyster shell on the side. Don't mix it with the feed, just offer it on the side.
The general idea is that chicks need extra protein to get started, basically the first 4 to 8 weeks. Then you can feed lower protein amounts to allow their skeletons and organs to mature and cut down on excess body fat. This is real general. There are a lot of ways to achieve this. The amount of protein does not have to be real precise. A lot of the recommendations assume you are in a commercial situation where you have thousands of chicks and you have to get your feed costs really as low as possible to get the best profit. That's not real critical to a lot of us.
Chicks can and will grow fine if you start them off with Grower. They will feather out a bit slower and won't grow as fast, but they will be strong and healthy. I feed a higher protein feed though to help them feather out faster so they are better protected from the environment. They can also eat the higher percent protein feeds for longer. That 20% Combined Starter/Grower or Flock Raiser can be fed from Day 1 until you switch to Layer.
I don't know what is available to you. If I were in your situation with those ages, I'd go with a 20% feed until the youngest were at least 4 weeks old. Then, if you wish you could switch to a 16% Grower or you can keep feeding a 20% feed until you switch to Layer. It really does not matter. You don't have to be that precise.