Adding Column Attributes For Custom Pipeline Component

I'm building a custom transform component. I want to mark some input columns as keys for deduplicating. In a similar way to the provided Sort component, I want to check those columns and allow pass-throughs (or not) for the others - so next to each input column name I need two checkboxes (1:use for dedupe; 2:include in output if 1 not checked). If a column is checked for use in the dedupe, I want some other attributes to be shown indicating how it will be used. How do I display the checkboxes to let users select which columns to include for deduplication, and then how do I add further attributes underneath (copying the Sort component's look) for selection?

Thanks in advance for guidance and pointers on this.