Refiners based on parent terms in Search results

Question

We have 3 level term set as Continent > Country > City

Examples are as below

• Asia > India > Pune
• Asia > India > Mumbai
• Asia > Bangladesh > Dhaka
• Asia > SriLanka > Colombo

In a list, we are using City term for a managed metadata column.

In the Search Refiners, we want to show refiners for all Continent, Country, City.

Any suggestions?