the closest thing you can get is whatsapp messenger and tell your friends to install whatsapp messenger on their bb.
it doesn't need pin so u don't have to add contacts manually. whatsapp auto detects your phone book on your iphone and it adds all them automatically which is nice, and it can do group messaging and broadcast messaging too.
a lot of people r using whatsapp these days, u will be surprised when you find out whatsapp messenger adds a lot of contacts from your address book by itself.