To give you an idea here is a sample diagram how the PBR works.
This is a setup of network with 2 ISP, if you want to separate the users for using different ISP.
You can use Router as your PBR, in my case I used Cisco Catalyst 3750 as my PBR to decide where the packet will pass thru.
Config on cataly 3750
STEP 1. First set your Vlan SVI's
!
interface Vlan2
ip address 10.2.0.1 255.255.0.0
!
interface Vlan4
ip address 10.4.0.1 255.255.0.0
!
interface Vlan3
ip address 10.5.0.1 255.255.0.0
!
interface Vlan5
ip address 10.5.0.1 255.255.0.0
!
STEP 2. Create Access-list, for filtering
access-list 10 permit 10.2.0.0 0.0.255.255
access-list 10 permit 10.4.0.0 0.0.255.255
access-list 20 permit 10.3.0.0 0.0.255.255
access-list 20 permit 10.5.0.0 0.0.255.255
STEP 3. Now create Route-map;
route-map routetoISP1 permit 10
match ip address 10
set ip next-hop 10.0.0.1
!
route-map routetoISP2 permit 20
match ip address 20
set ip next-hop 10.0.0.2
!
and now for here put the MAGIC!
!
interface Vlan2
ip address 10.2.0.1 255.255.0.0
ip policy route-map routetoISP1
!
interface Vlan4
ip address 10.4.0.1 255.255.0.0
ip policy route-map routetoISP1
!
interface Vlan3
ip address 10.5.0.1 255.255.0.0
ip helper-address 10.0.0.4
ip policy route-map routetoISP2
!
interface Vlan5
ip address 10.5.0.1 255.255.0.0
ip policy route-map routetoISP2
!
Here is the final config.
!
interface Vlan2
ip address 10.2.0.1 255.255.0.0
ip policy route-map routetoISP1
!
interface Vlan4
ip address 10.4.0.1 255.255.0.0
ip policy route-map routetoISP1
!
interface Vlan3
ip address 10.5.0.1 255.255.0.0
ip helper-address 10.0.0.4
ip policy route-map routetoISP2
!
interface Vlan5
ip address 10.5.0.1 255.255.0.0
ip policy route-map routetoISP2
!
ip route 0.0.0.0 0.0.0.0 10.0.0.1
!
access-list 10 permit 10.2.0.0 0.0.255.255
access-list 10 permit 10.4.0.0 0.0.255.255
access-list 20 permit 10.3.0.0 0.0.255.255
access-list 20 permit 10.5.0.0 0.0.255.255
route-map routetoISP1 permit 10
match ip address 10
set ip next-hop 10.0.0.1
!
route-map routetoISP2 permit 20
match ip address 20
set ip next-hop 10.0.0.2
!