Hide Contact List on Forms



I have a "contact list" field on my form to capture the best email to send a response to. Every time someone enters a new email, it is added to the dropdown list on the form. Is it possible to hide the dropdown values, and have the Contact List appear similar to an "open text" field on the form? Some employees use their personal email instead of their work email, and I do not want their personal emails visible to everyone who uses the form. I would switch this field to a Text/Number field, but then wouldn't be able to use the email in Workflow Automation.