How to get Jenkins variable with Groovy Script

[J.P. Hochbaum]

I have three drop down boxes and I want the first drop down variable to determine what is in the second drop down.  My algo below works with hard coding the first drop down variable and I get the return variable I need.  $TradingGroup is the variabale from the first drop down I am trying to populate this algo with.

def props = new Properties()

//initialize property file path//

def stream = new FileInputStream('/tmp/***')

try {

//load property file//

props.load(stream)

} finally {

//once loaded close the stream//

stream.close()

}

//get only property keys and convert into string array//

def parameters = props.keySet() as String[]

//println parameters

//def parameters=props.keySet() as String;

//parameters.each { println it }

parameters.each { def groupString = it.split(',') 

                println groupString

                 

                 groupString.each{ it.split(',')

                                  if (groupString[0] == $TradingGroup){

                                    var = it

                                    if (it!=$TradingGroup){

                                      println var

                                    return var

                                    }}

                                  }

                }