Apache - Reverse Proxy and LDAP configuration

I have an application which comes bundled with Apache. This Apache that is bundled into the program authenticates against an LDAP system. I need to install a secondary Apache on a different server that will authenticate against the LDAP through reverse proxy. Essentially the bundled LDAP will no longer be used to authenticate LDAP, only the second Apache with is set up with Reverse Proxy will.

Does anyone have any details on how this would look/work? Any example of this being done in the past?

My end goal for this configuration is that this secondary Apache will check one LDAP, if the user is not in the syste, then another LDAP will be checked. If the user is in neither LDAP system, then they will be rejected.

I know I will need to use mod_proxy and mod_ldap, I am just now sure what all conf files I will need to work with and how to put it all together.

Also FYI, the secondary Apache will be installed on a Windows server, and the original application with the first Apache is running on AIX.

Thank you for any help you may have.