SMS broadcasting-bulk system

i would like to get a program which will do the following, kind of multiply SMS delivery 1)a user sends an SMS to a short code with certain word (ie FAMILY) 2)previously this user has created a group called FAMILY in a website, this group include handset number for his family members for example 3)the SMS sent in 1) will trigger your application and the SMS will reach all the members in the FAMILY group 4)once any of the recipients reply to the email received, this will only reach the originator, not all the members budget is US$200 5)i have sms studio as the gateway, this interfaces very easily with any external application 6)some recommendations are welcome (this is some kind of basic twitter)