Way to Group MMS on iPhone4s and NOT have everyone see each other's replies?

When sending group message to iPhone users, you don't actually send an MMS or SMS, you send an iMessage (sent messages will be in blue bubbles instead of green ones). When sending iMessage to more than one person, you create a group chat, and everybody will be able to see all the conversation.

To actually send an MMS/SMS, you can disable iMessage in the Settings before sending the group message, then re-enable it later.

Unfortunately, this is something that you cannot change in iOS. There is a Group Messaging switch in Settings > Messages, but my experience has been that it does practically nothing.

One thing you can do that still isn't as fast as one single text to a number of people, but is faster then re-typing it, is forward the texts. Write one text, tap the Edit button in the upper right corner, tap the text you just sent, then tap Forward.