> Ahh, I see. So I can have a separate LDAP for my external cloud customers, while still maintaining my internal LDAP for my internal people / organizations?
Yes, this is entirely possible. Each Organization can have a 'custom ldap setup'.
> Would this be the recommended architecture or am I just complicating things and perhaps I don't need to create a separate LDAP for the external customers?
It's really "up to you". If you want to leverage the existing LDAP config, then you can inherit the settings from System into the specific Org. Otherwise, just use a dedicated LDAP config per each Organization.