Five is a lot easier than a whole other chapter and I think that will make a huge difference, since it sounds like the chances the PNMs will be able to talk to a greater number of sisters at the campus than in the experience I mentioned.
I wouldn't necessarily say it right out, but do it as soon as you can in a natural way. I think the explanation itself is the most comforting. And, like I said, if it's only a few of you, it shouldn't be much of a problem at all as long as you do tell the PNMs.
I think, if nothing else, it will be a fun experience for you.
I'm getting excited about helping with recruitment this weekend myself, so best of luck.