Parsing rest of locations if not found in memcached

[Ian M. Evans]

Please bear with me as I'm just beginning to read up on using memcached 
with nginx and might not have all the terms right.

Most of the memcached/nginx conf examples I've seen fallback to a 
backend if the key does not exist. Something that works, if I'm 
understanding correctly, with mongrel backends for RoR. Or they appear 
to default to a master 404 file as in some blog software where 
everything is run off a master index file.

My .conf file is Rubyless, just a collection of locations for PHP 
fastcgi depending on whether it a php file with an extension or without 
(we had a big thread a while back about handling the extensionless PHP 
files not matter what subdir they were in.)

So my question is this:

Is there a way to check for the URI key in memcached and if it's not 
there, just continue parsing the rest of the locations in the conf file?

Again, excuse me if I'm getting the concepts wrong, and yes, I know 
there isn't an "else" but here's the logic:

1) Check memcached for URI Key
2) If it's not there continue parsing the rest of the locations.

Again, I have very specific /location setups, so I don't think the 
/fallback {backend stuff} locations works for me.

Thanks!