How to set the priority of the methods that are included in groups in testng.xml file?

I have a class which has 2 methods. Each method is having a group associated.

Now I want to set my testng.xml file in such a way that when testcase TC1 executes, Method1() and then Method2() will be called and when testcase TC2 will be executed, Method2() and then Method1() will be executed.

Is there any way by which I can do that?