My DD (5) keeps arguing and fighting (non physical) with another girl (M) in her class. I think the blame is fairly even as they seem to antagonise each other at every opportunity. I am really good friends with the mum and am not letting it get in the way but is difficult to deal with. Example, we went swimming after school with M and a couple of other girls from DDs class. M knew someone else there and then excluded DD as much as possible. Just petty stuff like not letting DD sit next to her at the dge of the pool, refusing to pair up with DD. DD then got very upset. All normal stuff but it escalates into arguments with these two. On another occassion we had a girl from the same class over for tea and DD kept teasing M about how so and so was coming over. I have tried to encourage her friendships elsewhere and put some space between them but its exhausting. I am also feeling a bit 
as Ms mum can never see her daughter has any responsibility and know she has told someone about DDs behaviour on the occassions she was responsible for an argument but doesnt seem to be quite so forward in telling people if M is responsible. I am trying to not get too involved but is there anything else I can do? DDs and Ms teacher has commented on their behaviour and has suggested they are sepearted in yr 1.
When they are not aguing they love each other and want to go to each others houses etc 