Ability to automatically silence an alert when the data source is no longer available


I am using netdata 1.43.2 in an embedded environment (openwrt) on a wireless gateway. I have health configuration in /etc/netdata/health.d for triggering alarms when a wifi client uses excessive airtime. The alert works fine. However, if the client goes away (and thus the corresponding client airtime chart no longer has any new data) before reaching the threshold that would cause the alarm to be cleared, the alarm stays active indefinitely.

Relevant docs you followed/actions you took to solve the issue

I have looked through Configure alerts | Learn Netdata but did not come across any examples relating to this use case.

What I expected to happen

I would like to be able to mark the health configuration with a flag that indicates the data related to this metric is ephemeral and thus to automatically clear the alarm when the data is no longer available.
I suppose a similar scenario could be when a removable drive gets full and creates an alert due to usage reaching a certain threshold. But when the drive is removed, the alert should also go away (or at least, there should be a config knob to select that option, either globally or on a per alert basis).