MacPorts: extracting to multiple locations

Friends - I'm working on a cleanup of the xemacs PortFile - splitting it into xemacs and xemacs-beta, and ensuring that without the sumo option you still get the base packages. In doing this I'm discovering that I need to extract different distribution files into different places in the build tree. Is there a standard way to do this, or can somebody point me to another port that does something similar? Peace - John