Accessing data from trigger event data for template condition

Configuration
,
1

Hi,

I am using the Our Groceries integration and basically want to receive a notification only when the number of itmes on a shopping list reduces.

The state_changed event data, when adding/deleting an item to/from the shopping list, looks as follows:

event_type: state_changed
data:
  entity_id: sensor.our_groceries
  old_state:
    entity_id: sensor.our_groceries
    state: "2"
    attributes:
      recipes: []
      shopping_lists:
        - activeCount: 5
          name: Test_1
          id: JVzC0LxkYgxA52S5OUOJkd
        - activeCount: 5
          name: Test_2
          id: NBugC7PTU0xIy5vnWZBZPd
      icon: mdi:format-list-bulleted
      friendly_name: our_groceries
    last_changed: "2022-09-18T16:09:17.507057+00:00"
    last_updated: "2022-09-27T06:46:58.298137+00:00"
    context:
      id: 01GDYV5QZTXN9KS8MSRDCYD9AS
      parent_id: null
      user_id: null
  new_state:
    entity_id: sensor.our_groceries
    state: "2"
    attributes:
      recipes: []
      shopping_lists:
        - activeCount: 4
          name: Test_1
          id: JVzC0LxkYgxA52S5OUOJkd
        - activeCount: 5
          name: Test_2
          id: NBugC7PTU0xIy5vnWZBZPd
      icon: mdi:format-list-bulleted
      friendly_name: our_groceries
    last_changed: "2022-09-18T16:09:17.507057+00:00"
    last_updated: "2022-09-27T06:54:28.310660+00:00"
    context:
      id: 01GDYVKFEPG5AABSA79MD9PT4K
      parent_id: null
      user_id: null
origin: LOCAL
time_fired: "2022-09-27T06:54:28.310660+00:00"
context:
  id: 01GDYVKFEPG5AABSA79MD9PT4K
  parent_id: null
  user_id: null

For my template condition I want to compare the number of the attribute “activeCount” within old_state and new_state but I have no idea how to access this data. At the moment, my (non working) condition template looks like this:

- id: '1664202964250'
  alias: Benachrichtigung Einkaufsliste
  description: ''
  trigger:
  - platform: state
    entity_id:
      - sensor.our_groceries
    attribute: shopping_lists
  condition: 
  - condition: template
    value_template: "{{ trigger.event.data.old_state_attributes.shopping_lists.name == 'Test_1' }}"
  - condition: template
    value_template: "{{ trigger.event.data.old_state_attributes.shopping_lists.activeCount > trigger.event.data.old_state_attributes.shopping_lists.activeCount  }}"
  action:
  - service: notify.mobile_app_iphone
    data:
      message: Item on shopping list was removed
      title: Shopping List
  mode: single

Could anybody point me in the right direction?