Have this ant script:
<?xml version="1.0" encoding="UTF-8"?>
<project basedir="." default="all" name="helper">
    <target name="all" depends="first, second, third">
        <echo message="Running all targets"/>
        <property name="prop_all" value="pokus"/>
    </target>
    
    <target name="first" depends="second, third">
        <echo message="Running first target"/>
        <property name="prop_1" value="ppp1"/>
    </target>
    
    <target name="second" depends="third">
        <echo message="Running second target"/>
        <property name="prop_2" value="ppp2"/>
    </target>

    <target name="third">
        <echo message="Running third target"/>
        <property name="prop_3" value="ppp3"/>
    </target>
</project>

1, put breakpoint on line where prop_all is set
2, Invoke debug target all
3, Invoke Continue => only next one target is executed and execution does not
continue till breakpoint.