Goal oriented requirements analysis is one of the useful method to bridge the gaps between stakeholders needs and a requirements specification. Goals are structured as a directed graph, and its upper parts show the needs and its lower parts show the requirements. Although goals come from several different viewpoints, such viewpoints are not separated explicitly in such a goal graph. As a result, following kinds of problems can be occurred. First, we cannot easily remove or modify one viewpoint which affects several different goals. Second, it is difficult to analyze several different viewpoints separately and/or incrementally. For example, we cannot analyze a family of products simultaneously. Third, such a graph is not intrinsically scalable. In this paper, we propose a method to weave several goal graphs each of which represents a viewpoint. Several candidates of a weaved graph are systematically generated based on the structural characteristics of graphs for each viewpoint. By using this method, We can overcome the problems above, and we can easily propose alternative requirements specification if a specification is rejected by stakeholders.