How to make Junit run same method in from different class

I have diffident class that all of them contain test that is named a(), b() ,c() and using Junit 4. I also have a list that contains all the class that contains the same test. How can I run only test a() of all the class? How can I run these tests in parallel? I tried to use ParallelComputer but it runs all methods in the class (a,b and c).