I'd ask a TA, because they, through their sales reps, can sometimes get a better group offering than doing it yourself. Of course I'd first see if you can get a discounted rate on the Disney Resort yourself as a comparison. With that many people imho it's better to put the TA in the hot seat with one person as the main contact, but anyone can call the TA with questions. To get a group rate the rooms and tickets will need to be booked together. When I was a TA I did a group res for a family - 5 rooms at Carib. Bch., 2 vans for transfers, discounted air and drink coupons. The person in charge of the family had her hands full enough without booking and later reconfirming these arrangements and many times expressed appreciation for the pressure I took off her with all the questions and requests. Do a little research then go to a TA. If your prices are better and you want to be in the hot seat - go for it.