How to enable rules defined on one prometheus server to another prometheus

[manzajohn]

i have 2 prometheus(application and infrastrructure) deployments in the cluster, also i have alertmanager integrated with application prometheus, custom rules also were defined in application prometheus, things were working fine and i was able to receive PVC related alerts(metrics from infra prometheus) via opsgenie, suddenly it stopped triggering infra prometheus metrics related alerts, Any guidance on where should i start troubleshoot.
Below is my application prometheus alert rules, which is having pvc alert rule, but the metrics associated with this rule is from other prometheus

i Can see the metrics in other prometheus with below values and supposed to trigger warnings , but it is not

So how the application prometheus with alerting rules(pvc alerts) can trigger alert based on the metrics from other prometheus server?
Or should there be rules available in 2nd prometheus also? if so how to make it available