Inventory source variables

Hi All,

For an inventory with a project as source, you can enter an inventory file and environment variables.
Within that inventory we have an ansible.cfg with the vault password.

Everything works as expected when I set an environment variable as follows:
ANSIBLE_CONFIG: /var/lib/awx/projects/_X__name_of_project/ansible.cfg

Is there a variable that I can use that points to the configured inventory file?
Something like:
ANSIBLE_CONFIG: &inventory_dir /ansible.cfg

Thank you,

Raf