You should include some more info. Is your permit for a full size trip (16) folks or 8? Can the captain bring his own first mate? Have you arranged a for all food and boats (16 or 18 foot boats) and you just need a captain? How much will it cost? Who have you contracted with to provide shuttle and equipment? Has anyone in your group been down before? How will the duties of cooking, dishwashing, grover act be divided between members? How will you divide the costs?
If you are looking for someone to pay a full share of group expenses jump into a boat with a group of strangers and haul equipment for your group of kayakers you may have a problem but good luck!
Why does Pluto walk on all fours, drink from a dog bowl, and get treated like...a dog, while Goofy drives a car, wears clothing, and speaks in English?