Another way to set it a property, so that you would be able to access it from the rest of the steps is:
Have a groovy script with the following line
testRunner.testCase.setPropertyValue('GENERATED_ID', UUID.randomUUID().toString())
In the test request step where you required the property use as below
<some_request_element>${#TestCase#GENERATED_ID}</some_request_element>
In order to use above variable in another groovy step of the same test case is:
testRuner.testCase.getProperty('GENERATRED_ID')
//OR
context.expand('${#TestCase#GENERATED_ID}')
Regards,
Rao.