if you want to chat with them, then join a game you both have and chat away. I couldn't imagine someone joining a game , while there friend is in another game and everyone has to hear a one sided conversation like they are on the phone. or how about this, exchange phone numbers and talk. I personally don't see the need for cross play chat. or see why anyone wants it.
maybe it will be something implimented in the PS4. who knows.
Unfortunately cross chat is not possible with the PS 3 due to the way the system splits the internal memory. It is something they fixed with the Vita and the PS 4.
What do you think this is? XBL? lol
The party chat is a great feature if you have a group of friends you usually play with and like BS'ing with, but decide tonight I want to play some Skyrim, Dead Space, etc..., and don't want to miss out of the conversation.
A group of Dad's and I used it a couple summers back along with Google Docs to get a game of old school D&D going. Worked really well. Beers, party chat, my laptop and dice, oh yeah. lol.