I found one who says that he can make load-balance to unlimited routers (gateways)
on a "single LAN port" with the rb450g.
He made load-balance between 7 routers every one has 4MB download speed
so that's equal 28MB of download speed,
and he made one other LAN port take the speed of 8MB and other one 20MB
and you can see the attached picture
and he also disabled one LAN and name one LAN "MANAGE"
So if any one know how this can be done please explain it for me.