MMS is currently working on my phone in the US with AT&T.
I noticed when sending out a text to multiple recipients, the message sends as a group MMS. Any message that gets replied back to my group SMS stays in the same conversation as the original group SMS I sent out and doesnt get placed in a seperate SMS conversation.
Each message has the name from the person who sent the reply to the group MMS. Attached is a screen shot that shows the feature better.
Can you describe in more detail how you were able to do this? I cannot replicate your experience... Thanks.