Fecav8r or someone with more time/experience could probably share insights on the process, but what Lag said is basically what I know. We have a few guys on the line who came here after 3 years in corporate or training departments. They seem to have been connected in some way to people there previously and applied for spots when they found out about openings. I had one guy a few years back try for corporate, but they interviewed about a dozen for 1 or 2 slots. Its not an easy process, but it is another avenue.
Thank you Lord again for the postal wave of hiring. It wasn't "easy" when I went through, but it certainly wasn't this hard then to get the shot. Good luck!