Group coupons are generated for the discount to be applicable when a person is buying tickets in a bulk. For eg. if a customer buys 3 or more tickets he can avail a 20% percent discount on the whole price.
To create a Group Coupon click on "Group Coupon" in the manage coupon section. Give your coupon a coupon name and a coupon code. Specify the start and end date for the coupon (when it will be applicable). Also specify the coupon type whether customers can avail a fixed amount of discount or whether it will be certain percentage of the total amount. Specify the minimum and maximum quantity for which the coupon will be applicable. Also check the ticket type to which the coupon is added and click on Save to save the changes.