Two routers, two providers. How can I set up a common LAN between them by connecting with a cable?

Question

Computer networks

Apartment, two lines of the Internet, each hangs on a router. I would like to combine them into one locale. Those. Let the Internet be the same for everyone, but the locale is common so that you can expand something on one network and watch it on another, and not transfer information with your feet.

Answer 1

plug in the connectors
and dhcp limit the ranges
, however, the entire "locale" will be trampled into one Internet, not immediately, if you do not configure routes