Peplink Balance 380 multiple IP ranges

Morning

We have a situation where we want to seperate IP ranges between the following:

  1. Telephones 192.168.49.0/24 GW 192.168.49.1
  2. PC’s 192.168.50.0/24 GW 192.168.50.1
  3. Wifi devices that just need internet access 192.168.48.0/24 GW 192.168.48.1

I have tried setting up VLAN’s but our switches are 5 years old and there are multiple brands. Is there a way for me to do this without VLAN’s as I will have to buy 6 new Gibagit POE switches which will be rather expensive?

P.s I have upgraded to FW 6.3.3 build 3560

Regards
Gavin