[galaxy-dev] purge dataset at a different location

Dear Galaxy Developers, Because of specific use case, our transfer tool need to keep the datasets in a different location instead of the default location, so we'd like to purge datasets according to its "external_filename" (we found this column in the dataset table in the database). Is there a way or some code to modify so that when we try to purge a dataset or a history in Galaxy, the file located at a dataset's external_filename can also be deleted? Thanks in advance, Mark Xiao