I'm going to leave a search key on the server permanently, this means it will remain empty unless someone in this group starts a game on it, either via the lobby, or joining directly via the steam group list in game.

To start a new game on the server, you must have sv_search_key set to "ClanAAA". To do this:
1. Right Click Left 4 Dead 2 in your games list > Properties > Set launch options.
2. Enter +sv_search_key "ClanAAA"

Doing this when the server has 1 or more players connected will cause the server search in the lobby to time out, so make sure it's empty first.