You sound entitled, these kids are in foster care and you are angry because they are coming along on one family vacation. You’ll have your family for the rest of your life, they likely won’t. You say the family that you “grew up with” but did you grow up at all? Act like an adult.
You should reread the post comment you made earlier because that is absolutely not what you said. You said you wanted to vacation with the family you grew up with, not the new one. That’s saying you’re upset because they’re coming on vacation. If you’re so entitled that you would not have gone on a vacation bc there were foster kids there, your fam SHOULD have told the truth and let you not show, but clearly they wanted you there.