You define collector configurations (and their tags) on the Graylog side.
The sidecar_collector.yml file tells the Sidecar which collector configs it subscribes to.
So you can adjust the list of subscribed tags in the client-side YML file and you can adjust the tracked files on the Graylog side.
Unfortunately I don’t think there is a way to adjust the subscription tags in the YML file through Graylog itself. But you can always do that in other ways (like Ansible, Puppet, SSH, Powershell Remoting, etc).
In your case you can define a collector configuration, with its own tag. “evm” for example. To achieve what you want, you’d only put that tag into Sidecar config file on the agent-side.
Nope - I had the same issue when testing the sidecar, and we solved it in production by using Ansible to write the YML config out. All servers receive a set of tags based on which groups in our Ansible inventory they live in, and based on that I created the collector configs to tailor each group’s config to it’s particular needs.