There is an increasing need to interconnect biomedical ontologies. We investigate a simple but promising approach to generate mappings between ontologies by reusing and composing existing mappings across intermediate ontologies. Such an approach is especially promising for highly interconnected ontologies such as in the life science domain. There may be many ontologies that can be used for composition so that the problem arises to find the most suitable ones providing the best results. We therefore propose measures and strategies to select the most promising intermediate ontologies for composition. We further discuss advanced composition techniques to create more complete mappings compared to standard mapping composition. Experimental results for matching anatomy ontologies demonstrate the effectiveness of our approaches.