The PS4 2.0 firmware is coming soon and with it comes the Share Play feature. With this feature you will be able to play online with a friend even if they don’t own the game. However, Sony has confirmed that these sessions will be limited to 60 minutes before it will disconnect your session. However, the sessions do not seem to have a limit on them so you should be able to just open a new session.
It seems like an interesting feature that could certainly give it an edge over its competitors.