Extend Dropdown in BUI

Summary

I'd like to add some functionality to a particular dropdown without fully replicating it

Content

Sort of a generic and specific question in one. I'm approaching this as if it were Customer Portal where I can just extend a widget and add extra functionality to how it operates. I'm hoping I can do similar in BUI. What I'm basically wanting to do is retrieve more information to populate a dropdown above what it already contains. For example, when you click the dropdown for contact, it shows First Name and Last Name. Id like to hook the call to get that data, also grab the login (if its not already part of the backend payload) and