By default when select a database, Test Explorer displays all Runs listed by their execution time as here

Another possible view is to see test executions combined by the group they belong to.

Currently TestNG grouping is used to tag the Java methods which represent the testcases

Navigating to this view from the main Test Explorer page

Select the "Test cases by groups" perspective:

Select groups to see info about

Use the filter and click Submit

This is what you get after selecting a particular group