Redmine. How to create 2 custom fields with nested lists

For example, I want to make custom field with car models list. Of course, it would be too weird to cram the entire list in one combobox. The standard way to avoid this is a two combobox with nested lists, in first combo, user choose car brand, second combo loads in background li开发者_C百科st of models by this brand. Is it possible to create something similar in Redmine for the non Ruby programmer?

You would need to program some custom field types to do this. It would require both Ruby and JavaScript programming.