failed attempts Alternative solutions

The problem

In Google's SERP, when searching "foobar korea" (for example), their pages under www.foobar.com/korea/ show up in search results with the Foobar USA appended to the titles of all countries' subfolder pages in the SERP (ie. Lorem Ipsum - Foobar Korea - Foobar USA instead of the original ). We don't mind the rewrite. Our problem is how do we tell Google that this subfolder belongs to Foobar Korea and not Foobar USA?
From our own experience, after Google realizes that the organization name already appears in the title tag, they don't append it again.
This problem also appears in other country sites like Japan, China, etc.
It seems like Google is convinced that the entire domain is Foobar USA. Since Googlebot crawls from mostly US IP addresses, when the crawler tries to get the root domain www.foobar.com, it gets 301 redirected to www.foobar.com/usa/ where it finds and this is exactly what is appended to every subfolder page title where it doesn't exist.

Our failed attempts

We have tried adding structured data to the HTML pages with the name Foobar Korea, but that had no effect.
We registered the property separately in Google Search Console, but that has no effect.
We also have registered the www.foobar.com/korea/ as a Google My Business with the name Foobar Korea.
Are there any other ways to let Google know that these are separate sites and not to use the same title for all subfolders?

Alternative solutions

1. From our own experience with another client, we know that if we change the main site www.foobar.com/usa/ to be just (essentially letting Google think that it is just Foobar and not Foobar USA), Google will append just Foobar to all subfolder page titles if that doesn't already exist in the title.
2. As @closetnoc mentioned in the comments, we can also try changing the title length of the main page from to something like to discourage Google from appending the incorrect site name. From our experience also, this works, but is seems more like hiding the problem instead of fixing the problem.

The best solution is to signal to Google that each subfolder is a different site.
Just to be clear: This issue is not about rewriting the whole title in SERP. This issue is about Google appending the incorrect organization name to the title. The question is asking how to let Google know that this subfolder is a different organization.