For component-based systems, classical techniques for Worst-Case Execution Time (WCET) estimation produce unacceptable overestimations of a components WCET. This is because software components more general behavior, required in order to facilitate reuse. Existing tools and methods in the context of Component-Based Software Engineering (CBSE) do not yet adequately consider reusable analyses. We present a method that allows different WCETs to be associated with subsets of a components behavior by clustering WCETs with respect to behavior. The method is intended to be used for enabling reusable WCET analysis for reusable software components. We illustrate our technique and demonstrate its potential in achieving tight WCET-estimates for components with rich behavior.