help me out someone anyone because this is keeping me awake nights!

We have the possibility to go to disney world again next year and were thinking of a villa

friends have caught on to this and almost invited themselves. Well not quite, theyre saying things like "our villa" and "let us know when to pay" when we havent exactly offered.

The thing is it would make it more affordable but they'd probably want to be with us all the time and Im thinking of a family holiday

So what would you do? go with them , not go with them, try and establish ground rules??? help!