mod_rewrite is all about logic. If you understand the logic of 0 and 1, you'll pick-up on mod_rewrite quickly (try the tutorial linked in my signature).
If a file request does not exist AND
if the file exists without the first directory (member name)
capture the filename and redirect there.
With the sample code in the tutorial and the above pseudo code, you should be able to create the correct code. If not, show me what you've attempted and I'll get you there.