Java 如何设计套件文件以并行运行3个类，并按顺序运行其他3个类？

我有六节课（例如清酒）

希望其中三个并行运行，另三个按顺序运行。如何设计TestNG.xml

这是我想到的-

<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite thread-count="20" verbose="1" name="My Test Suite" 
skipfailedinvocationcounts="false" junit="false" parallel="none" preserve-order="true"
data-provider-thread-count="10" annotations="JDK">

    <test name = "my test" preserve-order="false">
        <classes>
            <class name = "com.mypackage.ClassA"/>
            <class name = "com.mypackage.ClassB"/>
            <class name = "com.mypackage.ClassC"/>
        </classes>
    </test>

    <test name = "test2" preserve-order="true">
    <classes>
        <class name = "com.mypackage.ClassD"/>
        <class name = "com.mypackage.ClassE"/>
        <class name = "com.mypackage.ClassF"/>
    </classes>

    </test>
</suite>

 class A 1
 class B 1
 class C 1
 Class D 1
 class E 1
 class F 1

===============================================
My Test Suite
Total tests run: 6, Failures: 0, Skips: 0
===============================================