As a User, I can select Test cases based on the total Estimated Total Time

As a User, I can select Test cases based on the total Estimated Total Time.

Inside a Test Plan, I want to be able to select Test Cases based on Estimate Time and view the total time of the selected Test Cases so that I can create Test Executions that should take a given time to execute.
For instance, I want to create Test Executions where all Tests included will take 6 hours to execute. The feature should sum the individual time of each Test and dynamically show the Total to choose which ones go in and which are left out.