Users belonging in mutiple groups cannot access group sharing.,

I add group test2 in test1, I want test2 being able to access test2's files. However, it seems I cannot do that. I do not prefer to change test1's gid to test2. I would like to keep it the current way where test1 group belong to both test1 and test2.

 [test1@fileserver2 test_permission]$ ls -al total 4 drwxr-xr-x. 4 root root 30 May 27 22:04 . drwxrwxrwt. 23 root root 4096 May 27 22:16 .. drwxrwx---. 2 root test2 6 May 27 22:04 test1 drwxrwx---. 2 root test2 6 May 27 22:04 test2 [test1@fileserver2 test_permission]$ id test1 uid=1001(test1) gid=1001(test1) groups=1001(test1),1002(test2) [test1@fileserver2 test_permission]$ cd test2 -bash: cd: test2: Permission denied