AFAIK Bluetooth is a 1-to-1 system and if I was planning a 1-to-many system I think I would use nRF24L01+ modules.
Bluetooth is simple as a 1-to-1 system. It is just serial by wireless. The nRF24s are a bit more complex but they work well. This Simple nRF24L01+ Tutorial may be of interest.
If you are thinking of buying Bluetooth modules you should know that the HC05 can act as either master or slave but the HC06 can only act as slave. For a communication link one of the pair must be a master.
...R