Multi-SMS MMS can I edit to list

First I didn't even know I had this feature and I suspect it was turned on as part of the 4.2 upgrade (changing defaults during an upgrade is a whole other Apple issue). Yesterday my daughter (3gs phone also) sent my wife and I a text message. My wife and I were sitting next to each other - both phones got message. The only reply I could do was to send to both of them - a waste sending to my wife - the whole conversation went on and on like that with phones beeping like crazy with unneeded messages.
Is there a way in this type of multi message to edit or delete one of the recipients? I guess I could turn off the multi setting but sometimes it is nice to know and see who is getting the messages.
Thanks,