Sheesh. BuffaloFang, you are obviously intimidated by this nasty woman - that sticks out like a sore thumb. If others are out money because of her, you have no right to make such a decision. I have no idea why you texted her or why you're "disappointed" that the so-called "friendship" is over. (I'm not asking - just commenting.) Your behavior regarding this woman has been .........strange. I'm sure if you keep texting her she'll find another way to use you. Good luck with all that. 
I agree--this seems harsh.
Also, BuffaloFang knows things we don't.
For one thing, maybe nobody else is really out money.
Maybe they all said, "Sure, we'll go together; sure, we'll split the housing and car-rental costs," without really knowing how many people would be there. If they haven't said, "If we get 4 people, that would be good," or if they've turned away someone else, or if they were recruited into the trip with the promise of 3 couples, or whatever, then yes, they've been impacted.
But I know that if I were planning a trip like this with several people, I would enter into it knowing that someone might end up backing out for one reason or another before it all comes to fruition. And I would be pretty upset if the organizing friend asked for money from someone who was backing out, especially when I wasn't actually out any cash yet, and hadn't been promised some sort of financial division of expenses.
But I would bet that this is not the case. And maybe we should all stop ordering BuffaloFang around about what to do with the monetary situation.