internally redirected requests

[nri.pl]

How to do internal redirect (which is the best way)? I do not want to apply
to this "include".
Maybe I can do something like this:

location /a { alias @app; }
location /b { alias @app; }

location @app { ... }

Should I use to this "error_page" or "try_files" if I do not dealing with
static files ?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,233074,233074#msg-233074