Here is my conversation with Cricket today:

Batman: is the group saving only available to new additional line and cannot be seen as adding existing lines to my account to get the discount?
Borginny: Actually the group save discount is automatically recognized if you add lines to an existing account. They work in the following way 1 lines = no discount, 2 lines = 10.00 discount, 3 lines = 30.00 discount, 4 lines = 60.00 discount and 5 lines = 100.00 discount.
Batman: but the lines to be added to my account has to be new customer right?
Borginny: It is not necessary for them to be new customers. If the lines are already active in separate accounts, you can merge them into a single account.
Batman: and get the group discount?
Borginny: That's right. Just please take in mind that for the lines to get the discount must be in a 40.00 plan or higher as the 25.00 plan doesn't qualify.
Batman: so, how do I add existing account under me to get the group discount?
Borginny: If you know the line's account access information (PIN code or security answer) we can access to the other line and merge it into your account
Batman: I see. Thanks.

Is that mean we can open a thread for people to group together and get that $100 discount in this forum?