group message issue iphones to galaxy s4
Ok so I just switched from a 4s to an s4 and I use group message very often with all iphone users. My issue is that I do not recieve any messages from my friends because there messages continue to send in Imessage. Ive read that once one phone number does not support imessage the group is reverted to sms or mms. This is not the case here and I am wondering what can be done.