Thus even if your regional team is of 100+ members (or say 10,000 members), members will not get unwanted junk messages from members but only from Admin. Though admin will receive messages from all its members and can then respond to the members privately. If any members message is useful to other members then admin can choose to broadcast such message.
Assigning of admins is web based - www.kranti.com
Other features in development (Scheduled for October 2 2017): Admin can announce events, ask opinion, communicate tasks and members can respond.