Yes, you can select individual bulbs. I believe the samples I include in my main function I show an example of sending the command only to one device as specified by its IP Address. Theoretically it is also possible to broadcast the command over the whole network with the tagged field and MAC Address properly set in the message itself to also achieve this result.
If you transmit the GetService message to the whole network, while listening for traffic in Wireshark (sorry I didn’t automate this in my code, but you could add it) the StateService messages that are returned will come from the IP address of the bulb(s) on the network. You can also download the firmware update checker tool from Lifx’s website or view your router’s config page to obtain these IP addresses.