User blog comment:IamJakuhoRaikoben/Chapter 389: The Twin Dragons vs. The King of Hades, Review./@comment-24546844-20140620163015/@comment-7418318-20140621090434

The guild hall was blown up by Elfman before anyone had the chance to make calls and as far as we know they never left Cana's cards until they arrived on Cube.
 * "Also I wonder where are the other guilds as I remember that someone in FT said s/he would be alerting the other gulids"

My best guess is that setting off one will cause a cascade effect that also makes the others activate, though I can think of other possibilities too. For example the Demons might only need a small anti-magic zone to revive E.N.D., so they don't care if one Face is insufficient to destroy the magic of the entire continent, since that's just an added bonus rather than their true goal.
 * "Why working so much to activate only one when there are thousands of them?"