Store variables outside of yaml file

Hi
I have a yaml automation which stores some tag values in a variable, then when the tag is scanned checks to see if the tag value is in the variable list and proceeds with the action. Here is a snippet

    alias: "SCD04 Handle Tag Scan"
    trace:
      stored_traces: 15
    mode: single
    # Hide warnings when triggered while in delay.
    max_exceeded: silent
    variables:
      # Map scanner device ID to terminal entity_id
      terminal: # used to direct messages to appropriate speaker for location of scanner
        xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx: media_player.kitchen_show
        xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx: media_player.hallway_echo
      # Map tag ID to user
      unrestricted:
        xx-xx-xx-xx-xx-xx-xx:
          user: person.1
          tag_name: Joe
        xx-xx-xx-xx-xx-xx-xx:
          user: person.2
          tag_name: Mike
      restricted:
        xx-xx-xx-xx-xx-xx-xx:
          user: person.3
          tag_name: Sarah
    trigger:
      platform: event
      event_type: tag_scanned
    condition:
      - "{{ trigger.event.data.device_id in terminal }}"
    action:
      - choose:
####################### Choice 0
          - conditions: # Unrestricted Access Tags - all states and all times 
              - "{{ trigger.event.data.tag_id in unrestricted }}"
            sequence:
              - variables:
                  media_player_entity_id: "{{ terminal[trigger.event.data.device_id] }}"
                  user_name: "{{ unrestricted[trigger.event.data.tag_id].tag_name }}"

The tag values are fairly sensitive, on a par with secrets. I want to store them in a separate file so I can exclude them from copies of the automation and maintain them in a single place. But not found a way to do this… Any ideas?

Appreciate any assistance.