Hong Kong to Zhongshan ferries

Thank you for the quick reply. We arrive at Hong Kong airport at 09.35 so wonder if we can get a ferry from another part of Hong Kong. We don't really want to wait until 15.40 for the airport ferry and don't relish a 3.5 hour bus journey. Can we get a train or taxi to another ferry terminal or is the Hong Kong airport ferry the only one to Zhongshan?