I agree with Trip, but I would do it in reverse.
Contact your Cruise Specialist and let them know what you'd like to do. After you decide, with their help, what cruise you want to do, they should be able to provide you most of the items you'll want to put together a cruise or cocktail party. They will be able to create other things that can help you get the word out. For example, we put together an electronic cruise sheet where everyone can see the pictures, get the prices, and check out the itinerary. We've even put together a web page so everyone in the group can see who's going and any news about the cruise. We'll even attend the party, give a slide show or show a DVD, have door prizes, and answer all the many questions first time cruisers have. So contact your Cruise Specialist first as there are many things they can do to help you get the word out there and get everyone excited about the cruise.