How to exclude the test folder from the test suite in testNG.xml file

I have a TestNG.xml file which contains one suite with name "newSuite" and this suite contains two test folders with name "abc" and "xyz" respectively. These two test folders contains different classes. Now, I want to exclude test folder with name "abc" without physically removing the test folder "abc" from the file or commenting it. Please help how do I achieve this objective.

My try: tag is not working at test folder level.

TestNg.xml

<suite name="newSuite">
   <test thread-count="5" name="abc">  <!-- test folder abc -->
     <classes>
       <class name="testabc.day2" />
       <class name="testabc.day3" />
    </classes>
  </test>

   <test thread-count="5" name="xyz">  <!-- test folder xyz-->
     <classes>
       <class name="testabc.day1" />
       <class name="testabc.day4" />
     </classes>
   </test> 
</suite>