Alerting when a router or switch is down without using dependancies?

Hello,

We are monitoring routers and switches for about 150 stores. I need help with the alerting of the following:

First alarm is when the router (first point of contact to the store) is down. When the router is down I don’t need an alert for the switch. When the router is up then the next step is the switch. If the switch is down I want to have an alert.

I have put the routers en switches in groups. All the routers in one group and all the switches in another group.

I know about the dependencies, but making en dependencies for 150 routers is a lot of work and I am hoping for a better solution something like this:

Can you please advice me on this one?