Can't get SMS Pro to do Group Chat with iphone users

[GroupChatLG]

Does anyone know how to get the Optimus Elite to be able to group chat with iphone users? The stock messenger didn't work, so instralled SMS Pro and selected the group chat function in the settings, but it still doesn't work. The replies come back in separate threads, and some replies come back and I can't see the messages at all. I have seen several threads where people have said it works with other phones, but wondering if it is this phone or operating system (2.3) that it won't work with. Or quite possibly could be user error. If you are able to do this on the Optimus Elite, please help?? Thanks.