I’m sorry about your girls not getting along. Just curious, did you introduce them on neutral grounds? It seems that the 4 year old doesn’t recognize you as leader of the pack and has taken over the household. You need to regain your position as leader and everything else will fall into place. This is not a difficult task but will take time, patience and commitment on your part. Have you considered obedience training? This would be helpful getting them to obey you. Why are they staked to the ground? This in itself might start aggression. A good idea would be to exercise them (45 min walk) to get rid of the pent up energy they have built up. A good exercise program would be to do this twice a day along with the obedience training. I would feed them separately, either in their crates or lock one in another room. This way you would know what and how much each one is eating and can save on starting a possible food aggression situation.
It’s really difficult to tell you how to handle the girls without being there. It’s quite possible you may be inadvertently doing something improper you are totally unaware of. In any case, I highly recommend you seek advice from a certified pet behaviorist. The sooner the better, so the problems don’t escalate.