From Local to National

As many of you have seen, my local is a small and struggling sorority. However, a very close friend of mine wanted to start up a national and when she mentioned starting an interest group at Kent State, I jumped at the chance to affiliate with a national. Both my friend and I have kept in contact with the representative from XYZ and this representative asked me what would happen if some of my sisters refused to do this. I haven't answered her back because I'm not sure. What happens if one of five of us don't want to do this? How do I approach the sister(s) without making her/them feel left out? I know that the majority of us want this. Any advice would be helpful.