Setting multi-folder file paths in patch to be run on multiple machines.

I have a piece that I plan to deliver as a single folder to be used with MaxRuntime. Rather than have a mess of patches and data on the same level I want to put the patch files in a folder inside the main folder (parent_folder/patchfolder) and the data files in another folder (parent_folder/data_folder). I can get the relative path to my patch file by sending a path message to a thispatcher object, but can't figure out how to construct a pathname that will let me back out of the folder my patch lives in in order to access the data in the other folder (basically I need to be able to create the equivalent of ./other_folder/file.)

Any help would be hugely appreciated!