Your idea of removing one of the hens with the first lot of chicks to hatch might work, but she and the chicks would have to be set up out of sight or hearing of the other hen.
Take the chicks away from the hens and raise them in a brooder. If you do not do so it is likely that the hens will abandon the eggs within 36 hours of the chicks hatching. Do you have an incubator ?