Possible to set a drop down option to {{GVAR}}

Is it possible to add a drop-down option to a Global or Local variable that is set from an input field?

I want the user to be able to create a thing and give it a name. I want that things name to appear in the drop-down selector list. I thought this would have been quite simple but it’s got me stumped.

Typically the way you’d achieve this in Axure is to create a custom dropdown using a repeater. Then when the user does whatever action, you can add a row to the repeater using whatever input they provided. The repeater will serve as the dropdown options.