Paperback, probably young teen, published in the 1990s, about a group of teens trapped in a house with a vampire

Question

I remember reading this from a borrowed copy from a friend somewhere between 1992 and 1994 (I vividly remember it being in middle school, which was only two years in length). A group of teenagers are trapped in a mansion with a vampire and are being stalked by it. The only bits that I remember distinctly are two vignettes:

• First, there was a girl in the group who got hold of a claw hammer, and began thinking in the narrative about her Irish heritage, and their history of kneecapping people, and how she'll use that to take out the vampire. I'm fairly certain that she gets taken out shortly thereafter.
• Another girl is caught by the vampire and she offers herself up as a willing sacrifice if the others get to go. The vampire then informs her that it will use its powers to ensure that her sacrifice is entirely forgotten, that no one will ever know she did this, and asks whether she still wants to. She still agrees to it, and he instead lets her go because she's the only one who offered a selfless sacrifice. I do not remember if the other teens are also released.

It was a paperback and I remember it as being similar to the various Christopher Pike / R.L. Stone teen books in appearance. I'm fairly certain it's not The Last Vampire, which seems to be from the perspective of the eponymous vampire and doesn't involve teenagers being trapped there.

Answer 1

I have a likely answer, which I'm confirming by getting a copy from the library. It looks like it's probably Caroline Cooney's Fatal Bargain, the third book of her "Vampire's Promise" series (the book was also released as The Vampire's Promise in 1993 before she decided to instead use that as the the name of the trilogy). It has the teenagers trapped in a building with a vampire and one person having to choose to be a sacrifice, and the names sound familiar.

The other two girls lived in that house with their families but in the last book, the house was abandoned and the kids were partying in it. They had woken up the vampire and he wasn't in a wishing mood. He gave them the option of sacrificing one for him to feed on so the rest could leave.

....

And in the last book, the vampire declares that if someone sacrifices themselves for the group, he cannot take them as a victim.