How do you promote sites on subdomains in different regions?

Question

Search Engine Optimization

There is an online store with subdomains. For 15 cities in which it has distribution points, 15 subdomains have been made. The list of categories and products is the same for all sites. Title, descriptions, keywords and h1 are unique for all categories and the main page. For all product pages, all these tags are the same. Yandex glues all domains into one, considering that sites duplicate each other.
Who faced a similar problem? Share your experience on how to make Yandex understand that these are different sites, and different people are following them.