I'd like to build the configuration of the attached figure, I've 3 routes to the internet router1, router2 and router3, I'd like to load balance using the 3 routes, but I want to know if it's possible to force route to the corp subnet (10.10.x.x) only trough router3 and all other traffic load balanced trough any of the 3 routes.
Thanks for your help.
That will work just fine. Create a pass firewallrule at LAN from source any to destination <corp-net>with the appropriate gateway. Other option is to use the default gateway and add a static route to the corp net through router3. Depends a bit if you want to route or to nat. In case you want to route you will need some static routes at the corpnetrouter and so on too and additional to that need some no nat rules.</corp-net>
Many thanks for your soon answer, I'll try to setup this.