Querybuilder: How to map Dynamic Values based on Key select

I need to show the dynamic values in richselect to the Query builder value field. I found this example (https://docs.webix.com/samples/66_querybuilder/01_initialization/07_custom_elements.html) where selecting ‘title’ key and rule, ‘value’ field populates values using Richselect.
I want the same feature but based on the key, the select values need to be updated dynamically?
How can I do that? Any examples?

Thanks