Hey there
I too started a group (unbeknownst of the already existing one) especially for all of us who want to play custom maps. Well no harm done, the more groups the bigger the chance of people snapping up on this. Note: most who play portal don't know about custom maps, which is unfortunate.
Join this group too and spread the word to all whom you ever play with.
http://steamcommunity.com/groups/p2cmgamers
