Receiving MMS issues

[RECav21#AC]

I can send and receive MMS messages to a group of people, however every time I receive a text back from a my friend in the group I can't read it. The phone doesn't move the message into the group text and I cant read it when I go to the message. I can see the message the preview list of all messages, but that's it. Any help, it's very annoying.

Thanks
Galaxy S3
Ver: 4.3