Have an option drop down on 'Group' messages allowing for it to be sent as a broadcast (type a message and send to multiple people as individual conversations. Recipients wouldn't be in a group chat, they would see a message as only they received it.)

I know this functionality can be changed in the logic of group messages, but I'd prefer it be an option any time I have more than one person in the To: bar.

Also, if those broadcast messages could stay in the list view as broadcast messages, you could go back to them and resend messages later to the same selection of contacts.