Without adding a customization, there are no public methods that return a List object containing the stateless transactions. The logic would have to iterate the VSI and perform what amounts to the exact same comparisons that DevTest VS Image Selection processing logic performs -- DevTest does this using multiple threads for performance reasons.
It is one thing to create a customization that matches the incoming request argument list (number of and names) to the argument list (number of and names) contained in the VSI. It would require much more complex logic that takes into consideration the argument list and applies Comparison logic (equal, less than, greater than, Regex, Property expression) and Match Styles (operation, signature, exact). Also, you need to consider the affect that DPHs have on the incoming request (removal of arguments, addition of arguments, etc.) and how your logic would cater for those scenarios.
Where would you anticipate adding this type of customization? As Prema pointed out, the inspection view in Portal provides some insight to this. Perhaps, parsing of the vse_matches.log into a tool such as Splunk or Elastic Stack could give some insights.