Actually this can be done quite easily. Assuming all 3 routers are in the same general area ... i.e. place of business or a very large home, and that each router is working off a different subnet (i.e. #1 192.168.1.x #2 192.168.2.x #3 192.168.3.x), you can have Router 1 server DHCP for every computer and have the other 2 routers act as access points to the network. And I'm also assuming that you have access to all 3 routers. Can you explain the need for 3 routers in your network? And are you certain that all 3 of these pieces of hardware are in fact routers and not switches?
Scroll down to #14 of the following thread:
It's not exactly the same situation as yours, but very close and can be resolved by doing similar steps. If you read through it and can get the general gist of what to do to turn routers 2&3 into access points and have them all on the same subnet handled by router 1 (i.e. 192.168.1.x) you should be able to accomplish what you want. Then you should be able to communicate with any computer on the internal network you create once you place them all in the same "workgroup" and set windows firewalls accordingly if they're in use.