If you didn't know already there is a trick that can allow you to bypass this problem. I read it in an earlier post and me and my housemate have been able to play together on our PS4s. You need to have two PlayStation accounts linked to each PlayStation. You will first log into the account that you do not plan to use, load up Destiny and reach orbit. Then close the application and log out. Now log in with your normal account and you should be able to connect. It seems to trick the server. Good luck! :)