Have the option that will create a new chat tab if one doesn't already exist, if the player hasn't joined typical spammy channels like "LookingForGroup" and "World" join them and add every single channel to the newly created tab. Additional option to remove the spammy channels from the default tab when creating this new chat tab.

This will help keep all the spam in 1 chat tab that the user never has to switch to, while allowing LFG Bulletin Board to read from all channels (assuming user selected it).