Setup Multiple ISP's For Redundancy And Persistence?

getting a secondary isp as back-up and redundancy...and work arounds for ddos's....I just thought that i could use a switch/bridgeable router that can act as a switch... and run that off the first in line off the #1 isp router. Instead of connecting the second into the isp port, i should be able to put the #2 isp line into that. and put #1 ethercable into one of the outgoing ports from the second. And keep all the pc's on the #1 as is....But it should still use both providers simultaniously...right? I have 3 or more routers that can do this, and i have used them like this and shared several pc's internet's other then the primary ISP. But it was shared through the pc. and separate NICS or wifi AP's. I currently have one that will autosense a gig, and have bought another router that can operate at a gig that i plan to put into the #1 position as it's the fastest one. And will keep 1 gig without variability. and also give me wifi n 450-700. And they both support bridgeing,repeating and network balanceing /shareing. This should be possible and i won't have to spend $4,000 on a router with 2 ISP ports, and only uses it as fail-over....=c this should use both simulataniously and balance workloads between each.