Prometheus monitoring with different targets (label for node exporter)

Is it possible to monitor a prometheus instance with different targets → node exporters?

We monitor a prometheus instance from another team.
The prometheus itself is configured and sends data.

there are serveral targets on it, which we can see on the prometheus target website.
Now we want to include thoes targes as labels.

I can add one another target label as “Explicitly map Node Exporter host” in the main rule.
But every additional doesn’t show a change (discovery) or if i set it to the first it fails.

Does anyone already have a proper configuration?

It it’s easier we can talk in Munich next week :wink:
Thx in advance.