In Grafana - how do I display 2 loki log streams joined by a key field

New to the “loki stack” and promql. pseudocode of what I need might look like this:

for each {app=“cronjob1”} ordered by date:

display selected fields

for each {app=“eventrouter”} where pod-name = cronjob1.pod-name:

display eventrouter log data

Any help, or even links to resources is greatly appreciated