How to setup two gateways in one subnet?

I have two routers, the first one serves as a internet gateway with internal ip address 192.168.0.1/255.255.255.0 and public ip 203.120.224.160. And the other router used as a backup internet gateway with internal ip 192.168.0.2 with a different public ip. Our goal is for all PC’s in the same subnet to be able to use the second gateway automatically when the first gateway (link) fails.

If I manually change the defaul gateway to the second one it works fine. But I want it to do it automatically, is it a way to get it done?