It would be ideal if communication in the Family Groups could go through the usual FamilySearch messaging system instead of through personal email. Or maybe both.
p.s. I think it was just within the past week that I deleted the Family Group message that used to be in my Messages box. So it did work previously. Now that I have deleted that it will not create a new message - oops, I did not know that it would not create a new message.
In the Family Tree Android app clicking the messaging feature brings up a blank message - no addressees, no ability to type a message, etc.
Resolution: I had another member of the Family Group send me a message and now I am able to send messages to the Family Group again.