I've setup an OC server over the past couple days, it's a hl2 based coop mod a bit like sc. The server running on the same ip as the other 2 server but on port 27015 (216.99.193.62:27015).
You can get the mod from there
mod website, you need to install source sdk base orangebox for the mod to work.
also the admins that are on my sven server are also on my OC server too.