I have a Samsung Galaxy S II and my phone provider is Sprint... have found that if you download Handcent you can send/receive and reply to all in group conversation threads. Here's how:
1. Download Handcent SMS
2. Go to the Settings Menu > Application Settings > select Default Messaging Application (Select All SMS & MMS)
3. After completing step two, select Thread Group Conversations (Note: You must select Handcent as your default message app. before attempting to thread conversations)
Hopefully this helps other Sprint/Android customers!
Bumping an old thread but I use Handscent. If I view the message details I can see the phone #'s of the people that were sent the message. But I have no way of knowing it was a group message. Is there an easier way to tell? Also, if I want to respond to the group is there an easier way than adding the other #'s manually to my reply?
EDIT: i install teh group plugin for handscent from the play store and i think i'm good now.
Based on Meka's comments in this thread, I installed Handcent 2 weeks ago so that I could work with group text messages. I'm happy to report that it works superbly and switching from the stock messaging app to Handcent was caveman easy. Wish I had done this a long time ago.
Install Hangouts and use that as your default SMS—it allows you to do group messaging (yes, even with iPhones from what I have tried) and the interface is much nicer in general anyway (and emojis!!!).
Go to messages then settings then multimedia then select group conversation then restart your device. Now you should be allowed to send your reply to everyone in the original group message
In newer phones, go into settings/applications/messages and keep hitting More Settings until you see Group Messages at the top. You can turn it on or off.