While some hospitals underwrite the expenses of the group, others conduct their own fundraising again, usually, using a collection jar during meetings. You may have a wider variety of potential speakers from your medical center and, if possible, have the opportunity to create educational seminars for health care personnel. The advantage of an ICA affiliation as a support group is a direct connection with their latest IC news and the opportunity to participate in national events. Be prepared for a minimal budget and to possibly use some of your own money to fund your group. It may be harder for you to find meeting space, as well.
Some hospitals only give free space to their own groups.
As first an ICA support group leader and then as a hospital affiliated support group leader, I made some mistakes at the beginning. We invested hundreds of personal dollars in our groups that, over time, became burdensome. If you are considering a national affiliation, research the organization fully and ask to see their goals, mission and, most of all, their financial records. You may also want to refer to the National Charities Information Bureau's Standards of Philanthropy to help you understand non-profit funding issues. If it looks good to you, then contact them again about starting a group in your area.