As per my understanding, in test suite all test cases are independent. But If there is any specific test case like validating if application is up and running before starting your other test cases within test suite.
You can mark that Test case as your start-up test case, If that will fail it won't run the suite Test cases.
Read more about it : Test Suite Editor - Base Tab - DevTest Solutions - 10.0 - CA Technologies Documentation
Hope that helps.
P.S. I will keep you posted if I will get to know about a way to abort the suite execution if any test case fails.