I need some help with people i know?

okay so this mate i have known only since the beginning of the year, we are really close and now i have started to date her friend. and now she got in to and argument with my gf and and their other friends. so i not asking whose side to pick i know that, i want to if i can resolve it anyway or get them talking again? cause i want them to start talking again cause i don't want to pick one but i looks like it is coming to that =( please help me not expecting to get them the best of friends again but talking can start hopefully lead to them reconciling