Select a RadioButton from Multiple RadioGroup in Android

MainActivity.java

public class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener {
  RadioGroup group1, group2, group3, group4;

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //referenced from http://www.tutorialforandroid.com/2009/11/select-radiobutton-from-multiple.html
       
        group1 = (RadioGroup) findViewById(R.id.group1);
        group2 = (RadioGroup) findViewById(R.id.group2);
        group3 = (RadioGroup) findViewById(R.id.group3);
        group4 = (RadioGroup) findViewById(R.id.group4);
        
        group5.setOnCheckedChangeListener(this);
        group6.setOnCheckedChangeListener(this);
        group7.setOnCheckedChangeListener(this);
        group8.setOnCheckedChangeListener(this);
}


private Boolean changeGroup = false;
@Override
public void onCheckedChanged(RadioGroup group, int checkedId){
  if (group != null && checkedId > -1 && changeGroup == false){
    if(group == frequencyGroup1){
      changeGroup = true;
      frequencyGroup2.clearCheck();
      frequencyGroup3.clearCheck();
      changeGroup = false;
    }else if(group == frequencyGroup2){
      changeGroup = true;
      frequencyGroup1.clearCheck();
      frequencyGroup3.clearCheck();
      changeGroup = false;
    }else if(group == frequencyGroup3){
      changeGroup = true;
      frequencyGroup1.clearCheck();
      frequencyGroup2.clearCheck();
      changeGroup = false;
    }
  }
}