If I have a family plan on AT&T and there are two individual text messaging plans on it, can I go into an AT&T store and have them change it to one unlimited family texting plan? Presently it's $40 per month for two individual unlimited texting plans whereas the one for everyone on the plan is $30 per month. It's only $10 per month, but there are two other people on the line that don't have texting because they don't want to pay for it. Thanks for the help!