Help, What would you do in this situation

[Alfred]

I have 3 groups of fish that spawn dates are
12/11
12/27
1/11
All are noticeable different in size but the same type of discus.
I need to move the youngest group to a larger tank, so I'm thinking I should
Move the larger fish from the middle spawn into the oldest spawn tank & move the youngest spawn into the tank with the smaller fish of the middle spawn?
Keep the competition for food on a level playing field.

What would you do?

[White Worm]

I've found that fish of similar size should be kept together. Still, I would keep the groups seperate in order to gauge each spawns growth, single out the best ones and identify the possible culls.