My dd's cannot be left with each other without descending into all out war. Dd2, 5yrs takes every opportunity to wind up dd1, 7yrs and she always ends up hitting of kicking her. When we leave the house they are best friends, but the minute going home is mentioned they start. I have tried talking to dd2 about not winding up but it is only little things she does that get a huge reaction. I have tried talking to dd1 and getting her to come and tell me rather than deal herself. We have had long chats about how to be nice/ stay away/ ignore etc. they get sent to their room for winding up/ hitting. But nothing works. We are at the point now where they cannot be left in the same room even for 10 mins watching tv without something happening. I try to spend time with each of them on their own each weekend, but they get upset if they feel the other one did something 'better' with me. My mum says I should just put them in the garden when they start which I am going to try but are there any ideas on here? Recommendation for books?