Have you checked this link to see if you qualify for any lower Group rates: https://swandolphin.com/offers/l try to keep checking the Swan to see if any lower rates open up as it's hard to justify the $400/night rate approaching some deluxe Disney hotels.
For example you can join AAA for less than $100 for a year, divide the $100 over the number of days of your stay. Also the Swan / Swan Reserve / Dolphin is moving to a $50 per day Resort fee so make sure that it is included your rate.
Dave