I see that yFiles GraphML files support "post-processors" that act on a parsed graph whose structure is defined in the same GraphML file: http://docs.yworks.com/yfiles/doc/developers-guide/graphml.html#ex_graphml_postprocessors . Is it possible to define a custom property mapping in the GraphML file (e.g., using the syntax in the "propertiesmapper.xml" temp file) then automatically apply it to the graph using a post-processor?