I feel your pain...we had some very irritating neighbors that started out as friends, slowly became a very one-sided relationship, the husband would borrow stuff and return it busted, or never return it at all, their adopted daughter was the devil, I swear
She would torment my boys, just show up whenever and walk in my house...jeez, the stories I could tell you. We eventually stopped being "there" for them and just rode it out, knowing he'd be transferring someday with his job. It took years, but they finally did move. It was tough taking the high road though, just tolerating 'em, but with my then hubby and I working all of the time and them seemingly home a lot, last thing I wanted to do was make things worse. I would have come home to all sorts of things they could have done while we're at work, so it was best for us to just wait out them leaving.
Hopefully your neighbors will eventually do the same. Until then, I'd just turn the other way, keep your girls from them and their kids and go on with life. If you make things worse and they stick around for a while, it could lead to all sorts of problems. You don't want that in your life, police being called, filing complaints, etc...
Good luck