How to connect 2 routers to one local network?

Question

network hardware

There are two routers "Megafon 4G + (LTE) / Wi-Fi R100-1". Each of them distributes the Internet through its switch: the 1st router for 4 computers, the second for 5 computers. If you connect these two switches, you get a shared network access. It is convenient for the administrator to manage a network of computers. At the same time, how to leave Internet access for each group, as it was before the state of a separate group, i.e. so that users spend only their own traffic?

Answer 1

I tried something like this, but I made 2 mistakes. I made different subnets on routers: 192.168.1.1 and 192.168.0.1 and completely forgot about DHCP. Thanks for the advice.