Running multiple load test cases in parallel

I have created a test suit with multiple test cases and each test case has a load test case configured with its own configuration. I have selected my testsuit and product-testsuis to run in parallel. When I try to run entire testsuit with loadtestrunner, each load test case is getting executed in sequential. How can I make all load test cases to run in parallel.

Surprisingly when I run testrunner on the testsuit, all test cases get executed in parallel.

Your help will be highly appreciated.