Is their a special discount for group? I am planning on a birthday party and need to purchase 23 tickets for 1 day.

They have group discounts for 15 people or more. Here is a link where you can get more information https://disneyparks.disney.go.com/disney-group-rates/

The surrounding hotels I've heard had group ticket sales. I would first call the park and ask and if they say no then check the surrounding hotels .. it doesn't hurt to ask