How to trigger life event when either the employee or any of the covered dependent's ageband change

Summary: How to trigger life event when either the employee or any of the covered dependent's age band changes ?

Content (required):

We have a requirement that rate should be a sum of the age banded rates for both the employee and all of the covered dependents. So if employee and spouse are in age band 50 - 55 and have 4 children aged 20, 18, 16, 14. Rates based on age bands of the employee + spouse + each of the children is to be calculated. Since the no of children are not limited, i used a rate calculation for post enrollment fast formula.

However, i am facing a challenge in setting the Rate recalc/age changed life event. Since we cannot set this via trigger on any table/column and a supporting person data changes life event trigger, i am considering setting up: