AWX and group_vars, host_vars from external source

I am using an Git repo as a source of my inventory. This repo also contains group_vars and host_vars directories. When using regular Ansible, Ansible will look for those directories in the location where the hosts file.

With Ansible via AWX I have the option of using an “external source” for inventory. When I add the URL of my Git repo I can select the host file or root. I tried a configuration with a host file in the root and a configuration with the host file in a sub directory. With both options the directories group_vars and host_vars are ignored as far as I can tell.

The documentation is a bit vague on the issue.

Keeping variable data along with the objects in Tower (see the inventory editor) is encouraged, rather than using group_vars/ and host_vars/. If you use dynamic inventory sources, Tower can sync such variables with the database as long as the Overwrite Variables option is not set. 26. Best Practices — Ansible Tower User Guide v3.7.0

I don’t see AWX retrieve those vars? Variables in group_vars and / or host_vars? Or is this sync ability limited to the host file? If it is possible, how should this work?