Hi Auntie_Em4!
I have an article for you here that can hopefully help you understand group messaging a little further:
iOS: Understanding group messaging
http://support.apple.com/kb/HT5760
Specifically, I believe this section of that article answers your question:
If you send a message to multiple recipients without group messaging in use by the sender and all recipients, an individual message will go to each recipient using either SMS or MMS. Responses to these messages will be delivered only to the original sender in seperate messaging threads.
Take care, and thanks for visiting the Apple Support Communities.
-Braden