So maybe someone can suggest an alternative set up to what I have:

Code PHP:
class ftp {} // handles opening ftp connections, listing files, downloading files, etc
class mongo_conn {} //handles mongodb connections
class dur_files extends ftp {} //dur is a type of file I regularly deal with, allows me to list dur files, download them locally, extract them (gz) and then calls dur_import
class dur_import extends mongo_conn {} // handles the import of a file from dur_files, ideally I'd extend dur_files as well as mongo_conn, but I cant, so Im calling this class from within dur_files

10,000' view is that I need to be able to list files that are in a directory, determine if they are loaded into mongodb, pull them down, extract and then load line by line (all this is programmed) but I'm running into organization / extension issues.