The Hue Bridge does not set up its own Wi-Fi, but uses the Zigbee network. This means that the Bridge is connected to the router via a LAN cable and the lamps communicate via Zigbee rather than Wi-Fi.
This means that your balcony lamps do not need to be in the Wi-Fi range, but within Zigbee range - either directly to the Bridge or to another Hue lamp that is closer. The lamps form a mesh network, i.e. they pass the signal on to each other and thus automatically extend the range.