использовать vrf или pbr
для VRF будет примерно так

ip vrf  vrf1
int vlan 100
 ip vrf forwarding vrf1
 ip address 10.0.0.1 255.255.255.0
int vlan 200
 ip vrf forwarding vrf1
 ip address 172.16.0.6 255.255.255.248
ip route vrf vrf1 0.0.0.0 0.0.0.0 172.16.0.2

для PBR

ip access-list extended acl-clients-10-0-0
 permit ip 10.0.0.0 0.0.0.255 any
route-map gate2 permit 10
 match ip acl-clients-10-0-0
 set ip default next-hop 172.16.0.2
interface Vlan100
 ip address 10.0.0.1 255.255.255.0
 ip policy route-map gate2