Need to run 'test step' asynchronously using groovy

Hi,

Is there a way to run a test step asynchronously using groovy without getting into threading ?

I have to test a scenario, where a single request postes multiple responses to different topics.

So, I need to run a couple of test steps asynchronously. (waiting for response)
On running the third test step, response gets posted to the above test steps.

Rgds,
Ab.