Android texts with Synced Iphone and Mac

I have synced my new iPhone 5s text messages with my iPad and Mac mini. When my friends with iPhones send me a message, I get the message on my iPhone, iPad and Mac. However, if a friend with a Samsung Galaxy sends me a text message, it only goes to the iPhone and never gets propagated to the iPad or Mac. Any suggestions to what I could be doing wrong?

Thanks.

Ray