url routing to dynamic file name

[eluser]RaZoR LeGaCy[/eluser]
I need

Code:

http://www.hellhorror.com/demon-names-16.html

to go to

Code:

http://www.hellhorror.com/demons/demonology/16/DYNAMIC-NAME.html

with a header of 301 permanent redirect

How may I do it??
In routing, a seperate file that checks the segment then checks the DB and inserts the file-name?

Best optimized solution please.