How to connect 2 Internet connections in an organization?

Question

Computer networks

Hello.
There was a question: at office 2 adsl lines enter (at the first ip, we will assume 172.16.16.1, at the second 172.16.16.2 - static). Accordingly, there are 2 Rostelecom routers. Also installed d'link des 1016a, which connects a couple of dozen computers.
Both adsl channels are required.
To do this, I connect both routers to the gateway, then on computers that should work on 1 line, I prescribe ip 192.168.1.10-20 in the settings, and as the default gateway I prescribe the IP address 172.16.16.1). I set the dns settings to standard Rostelecom.
However, the internet is not working. Tell me what I'm doing wrong.

Answer 1

I solved the problem by setting the gateway on each computer.
One router had an internal ip address of 192.168.1.1, the other - 192.168.1.2. Accordingly, on computers that were supposed to use a particular Internet, the gateway was chosen accordingly.
Thank you all for your help.

Answer 2

it is necessary that the 1st line is used by 4 users, the 2nd - by the rest. Moreover, a server is connected to the gateway, which should also be visible from all computers. Therefore, you need 2 subnets, in each of which work will be carried out in parallel.