Deadman with alert recipients dependent on hostname

InfluxDB 1 Kapacitor
1

I would like to construct a typical deadman that alerts when a host fails to send data after a specified delay. Kind of like this:

var data = stream
    |from()
        .database('telegraf')
        .retentionPolicy('autogen')
        .measurement('system')
        .groupBy('host')
    |deadman(1.0, 10s)
        .id('{{ index .Tags "node" }}')
        .message('Server {{ .host }} is OFFLINE')
        .email()
        .to('recipient@test.com')

However, I need the alert recipients to depend on the hostname. I currently capture the intended recipient for each host in a separate alert measurement, ‘host_alerts’. In that measurement host is a tag and the alert recipients are then defined by the latest value of a ‘alert_recipients’ field:

select last(alert_recipients) from host_alerts where host = 'foo'

If the latest value is an empty string, then no alert should be sent.

I’m not sure how to use the results from a separate query that is parameterized by a tag like this.