Sorting multiple lists by a list item

// loop the number of tag blocks - where r is the number of blocks which is determined by an XPath count (1-500 subtag blocks)
def masterArray = []
while( x < Integer.parseInt(r) ){
   x++

   // increment the block number to test each subtag block - this increments the Xpath [] to collect each block of data
   testRunner.testCase.getTestStepByName('PropertiesXML').setPropertyValue("block number","${x}")

   // Run the write to XML routine to write XML values to the properties file - this collects the data from the WS XML via XPath
   testRunner.runTestStepByName("Write to XML")

   // The Xpath values are stored in the properties file
   a = testRunner.testCase.testSteps["PropertiesXML"].getPropertyValue("block number")
   b = testRunner.testCase.testSteps["PropertiesXML"].getPropertyValue("code")
   c = testRunner.testCase.testSteps["PropertiesXML"].getPropertyValue("eventDateTime")
   d = testRunner.testCase.testSteps["PropertiesXML"].getPropertyValue("comment")
   e = testRunner.testCase.testSteps["PropertiesXML"].getPropertyValue("transmissionStatus")
   f = testRunner.testCase.testSteps["PropertiesXML"].getPropertyValue("transmissionVersion")

   // The Xpath values are taken from the properties file to create a list
   def myList = [a,b,c,d,e,f]

   // Add the myList to the Master array in block x
   masterArray.add( myList )

}