How can I play with people on ps3 when I'm on ps4 on need for speed rivals?

I too have this question, and have friends asking it all the time with no information on the subject.  Nothing that says you can't do it, nor how to do it.  If we can't (BIG MISTAKE IF THATS THE CASE) at least let us know.

You are incorrect.  Even Sony says its up to the developers.  This is not a platform issue, it's a game issue.  You can do it if the game is developed that way.  Check out DC Universe.  CAN NOT cross platforms is true, Sony to Microsoft you can not do, differenct providers, network, etc... this is same network, same platform, same developers.  Its on the game builder.

dc universe is a bad exsample it like ff11 i say dynesty warriors is a better exsample  its not mmo and its crass plateform and cross saves and he's right its up to the devlopers to decide to do it.