How to modify tcp ip stack for dual adsl connections

I have two adsl connections. One come from a wireles, wiif modem, a second one from a THOMPSON 5G580 Modem/Router. They are both ADSL from different ISP'S. They come into a desktop switch (the adsl tp link TL-SF 1005D).

Is there anything you can suggest i can tinker with at the TCP-IP stack to make them work together in a sort of scheme? (50/50 perhaps) for the purpose of workload balancing and wider bandwith?

I would appreciate any comments about it. I will try to get additional software but it look like i will have to throw some money at it. I would rather experiment with the tcp ip stack or any other suggestions first. (it is more fun that way).

Thanks in advance for any speculative thoughts about it.

Joel.

If you can get an old PC you can install a special Linux or BSD router distributions and make your own custom router.

Yes, I have played around with a couple of PC based routers over the years for special applications like what you are doing.