Wireless Communication from one to multiple


I’m doing my own home automation in my room and the way it works is by having an Arduino UNO and Ethernet shield connected to the router. I need this board to communicate wirelessly to the multiple other boards next door. I also need it to be controlled by the web. Any help on doing this and what I would need would be great. Thanks.

Does the master (the Arduino with the Ethernet connection) need to connect to the others (slaves) all at the same time or one by one?

And does it only need to transmit from master to slave, or will the slaves need to send data back to the master?

How many bytes of data will the master need to send?
And how often?

The nRF24L01+ 2.4GHz transceiver modules are easy to use and cost about £2 each.