Alternate built-in messaging apk ? Why does group messaging not work ?

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http://forum.xda-developers.com – There are some select samsung and motorola phones (for vz) that can send and receive group texts within the default messaging app. Is there anyway to flash that single APK to gain this function ? I am running bigxis jellybean, and when i send a group message, it sends to all people within a message, but when i get replies back, they come as seperate. Does this have anything to do with tmobile maybe ? (HowTos)