Contact List Update Automation

I have a selection dropdown for a Contact List in a form. Is there a way to automatically update that dropdown contact list rather than manually adding and removing people as they leave or join my organization?

I want to try to update contact lists and contact list dropdowns in forms across all my smartsheet templates. At first I thought I could use cell linking, but that only works if I want to update a column or row of contacts. I cant find how to link to a contact list form element so I dont have to manually update (remove/add) contacts across all my forms.