As an experiment builder and analyst

I would like to create advanced ratio metrics by combining events in the numerator and denominator.

Importantly, if the metric in a ration metric is custom, I need to be able to set custom properties in their definition.

So that I can more easily and accurately define my target metrics without extra work.

Use case: i use a custom property called 'environment' that sets 'dev','qa','prod' so I can distinguish between events in different environments. Without that property, ratio metrics cannot utilize the event.