Selective rewrite/redirection

Hello, everyone, I need some help. I have this:

server {
listen 443 ssl spdy;
server_name example-01.com;
[...]
}

server {
listen 443 ssl spdy;
server_name example-02.com;
[...]
}

server {
listen 443 ssl spdy;
server_name example-03.com;
[...]
}

server {
listen 80;
server_name example-04.com;
[...]
}

server {
listen 80;
server_name example-05.com;
[...]
}

server {
listen 80;
server_name example-06.com;
[...]
}


What I am looking for is to automatically redirect all non-SSL to SSL for those domains (with www, and without) that are running SSL, while still allowing regular non-SSL (with www, and without) access to those domains running without SSL. What would the simplest way be? Thanks!