Installing Drupal on a third-level domain

Hello, Ivan!

I have encountered a problem.

There is a site on Drupal 7 that has been running for about a year. Everything is great, but recently it has become necessary to divide

users by regions: Moscow, Samara, ...

I understand that this requires creating third-level domains, for example, moscow.****.ru, samara.****.ru, ...

However, the catch is: there are many cities, and consequently, there will be many third-level domains,

and do I need to install Drupal for each one???

So I have two questions:

1. So, there is a main site: ****.ru. It already includes information for all regions of Russia. Is it possible to create third-level domains without installing Drupal for each region? (The third-level domains will not be standalone sites, but will only slightly differ from the main site, i.e., the main site contains information from all sites ***.****.ru)

2. If the section, for example, News, is the same for the site ****.ru and ***.****.ru, how can I ensure that when adding news to the main site ****.ru, it also appears on the site ***.****.ru?

Thank you in advance!