My Siblings and I are Different

What if the Potter's had nearly as many children as the Weasleys? Before Lily and James are killed the children all grow up together. But when Harry is just a year old the Potter parents are killed and the six children are split up. The three youngest go to the Dursley's while the three eldest went to the Weasleys, due to the already clear bond between the eldest Potter and eldest Weasley. The siblings still keep in touch but the five eldest all agree to keep their little brother in the dark as long as they can about magic. Let's see what happens once Harry joins his sisters in the world of magic.