code: function sendPrivatePayments(device_address, arrChains, bForwarded, conn, onSaved){
  	var body = {chains: arrChains};
  	if (bForwarded)
  		body.forwarded = true;
  	device.sendMessageToDevice(device_address, "private_payments", body, {
  		ifOk: function(){},
  		ifError: function(){},
  		onSaved: onSaved
  	}, conn);
  }
docs: unlike similar function in network, this function sends multiple chains in a single package