My 19 y/o stepdaughter used to come over with her 2 younger siblings since she was 10, when her dad and I started living together.

She was always distant, flinched when I tried to hug her, started fights with her sisters on purpose, lied to get cell phone account number and then let her mom have the credit from  the phone we bought her, etc. After an incident when she was 17 and she made motions like she was going to hit me, she went to live with her mom. She was always like an angry time bomb, sulking but not answering us when we asked what was wrong. She would just say - "I don't know, or nothing". A year ago my dh said was talking with her again. He finally told me that shortly after she went to live with her mom, she gave him an ultimatum "leave her and get back together with biomom, or I will not speak to again." He chose me. He explained that he'd rather have all his teeth pulled than ever go back to his ex wife. She hadn't spoken to him in 2 years. Now she is coming around, calling him and saying she wants to "stop by for this or that" or "come over for dinner" etc. He asked me and I told him that he can have a relationship with her, but I am not comfortable being around her or having her in my home. So now she is working on the other skids, her younger sisters, 17 and 15. They have been asking relentlessly for her to come over and asking why its such a big deal. DH and I say no, and he says he has has a long talk with them to explain why their older sister is not welcome here. Meanwhile older sister was asked to call me directly and apologize. She has not done this. She has, instead, lied and told her sisters that she left because their dad raised his hand like he was going to hit her 2 years ago, and told an alternate reality version of what happened between us - when I asked her to close the freezer door 3 times, and she raised her hand and came at me like she was going to punch me, In her version, I "closed the freezer door on her head." Nope, never happened. But guess what, she can tell her little sisters anything, and they will believe her. So, I am again defending myself against her lies and manipulations. 

We are going on vacation soon, and taking her 2 younger sisters, who live with us part time, The 17 year old sister is repeatedly asking us for the address of the home we are staying in, She repeatedly asks her dad if their older sister can come, or stop by, I said no, and he backed me up. But my concern is, I am afraid older sister will show up unannounced, uninvited, and try to guilt her dad into letting her stay. I have brought this up with him, but he doesn't believe it will happen. I bought a small hidden camera to wear and keep in my purse for whenever I have to deal with older sister - or if she should show up. That way I have documentation of what actually happens, so she can't twist it for her own use later. I told DH about this and he understands, but thinks I am over reacting. This girl almost ruined my life once, I don't want to give her another chance, But i also don't want to risk my relationship with my other stepdaughters, whom I love. Everytime I think about seeing the oldest stepdaughter again, I have a panic attack. Her and biomom, who are both narcissists, will manipulate anyone to get what they want. I have lived through it, and won't go back to that hell again. What do you think?