Sophos UTM as default route on core switch

Hi,

I have a network with multiple vlan. the default gateway of each is the core switch. and all traffic must be routed to sophos utm

vlan 36 192.168.36.0/24 gw: 192.168.36.1 (core)

vlan 37 192.168.37.0/24 gw: 192.168.37.1 (core)

sophos internal ip 192.168.37.4 

the question is, how can sophos utm accept the traffic coming from 36.0? what routing should i define?

Thanks!