Soup UI Pro - run two (or more) test steps simultaneously

I would like to set this test case up:

Step1. REST request

Step2. Magic script that parse json-response and trigger step 3 & 4 to run simultaneously (not first step3 and then step4).

Step3. REST request

Step4. REST request

Step5. Almost same magic script that parse step 3 json response nad trigger step 6, 7 and 8

Step6. REST request

Step7. REST request

Step8. REST request

In examples and tutorial I've seen:

'testRunner.testCase.testSuite.testCases["testCase name"].run(null, false)'

I guess it's the '.run(null, false)' part I need to understand and modify to be able to run two steps at the same time.