Yes, just use software serial. Remember to keep your baud rate low, say 9600 or 4800 as software serial can't do more than about 19200 baud on an UNO - you should use AltSoftSerial.
On the master you send out the message with the ID of the slave you want to talk to. In the demo code from my previous example, I would send out <5,0> to turn off the LED on node 5 for example.
Don't forget that this is your comms protocol, so you decide how you send and receive messages between your master and your slave devices. You may want to add in other parameters such as a command ID so your message from the master might be <5,2,3> for device 5 command 2 data value 3. You might want to ask a slave for some reading, so maybe <8,1,0> might mean device 8, command 1 (where command 1 to the slave means read a temperature and send it back), and the 0 is just padding to keep the 3 fields. When your slave sees this, it can respond with the temperature back (assume your master is device 0) - so <0,1,22.5> might be a response from the slave to the master saying that in response to command 1, here's the temperature of 22.5 degC.