Autoresponder Reply-to Email only allow text - can't select field

I am working on this form: https://form.jotform.com/53133906041143

There is a hidden field that updates based on the dropdown selection for branch location. 

I am trying have the Reply-to email address on the autoresponder link to this hidden field. However, when I go to set up the autoresponder, the field for Reply-to Email is only allowing text - there is no drop down to select a form field. 

Any help?

Thanks,

The autoresponder is the email notification sent to whoever fills the form up.

As per your explanation, you need the notification to reach a particular branch in your organization  whenever someone gets the message and decides to "reply to"

If that is the case, simply add the variable to the field

Here is my demo form, https://form.jotform.com/60126344300945

whatever form you choose from the options, you'll get the reply to with the said email address.