Thats the problem, even if you have the same game on xbox or ps4 you can only play against those on the same platform. There is no way currently of playing between different consoles.
At 7 this won't be a factor as such but my son is 13 and it is very much you have to have the console your...
We have both an Xbox One and a PS4. The PS 4 gets much more use than the xbox in our house. The best thing about the xbox one over the PS4 is the kinect but sadly microsoft got bored of that pretty quick so there is only limited games that use it but its great fun. The main reason the PS4 gets...