Communication across accounts for charter organization

Our Charter organization has three separate groups that uses TT. Our AHG Troop (TX1613), Boy Scout Troop (226-Plano), and Cub Scout Pack (226-Plano). We would love to have a way for the charter organization to send communication that would go to all 3 groups without having to send three separate emails. Also, would love to be able to view a calendar that incorporates all three groups activities so, when scheduling, we don’t have conflicts.