Hi there,
The SG300 does support routed switchports. First you need to put the SG300 in router mode:
set system mode router
Once rebooted, you can configure an IP subnet on each interface:
!
int gi1
ip address 10.10.1.254 /24
int gi2
ip address 10.10.2.254 /24
int gi3
ip address 10.10.3..254 /24
!
cheers,
Seb.