Welcome, Hazel. I've done some work with Multisite (I use it for my personal/biz sites), and I know there are some others in the group who also have experience with it. Post a more detailed description to the mailing list.
Meet other Apple iOS iPhone iPad Developers, Entrepreneurs, Startups, Investors from San Francisco Bay / Silicon Valley Area to discuss how to build and promote your iPhone based business. This is an open meetup. You are welcome to participate, or present your iPhone app, ideas, or solutions.