Delayed group text/iMessages

I, as well as many of my friends, have this same issue and it's getting really annoying and old, quite frankly. The problems seems to be when the group has a mix of iOS devices Andy android devices. The Android users always get all of the messages, however, the iOS users will get messages severely delayed. It doesn't seem as if there is any pattern to which iOS user gets left out. It seems as if it will be a different person each day. I'm in a few different groups like this and each one experiences the same issue. We've all done the standard things like resetting and turning things on and off. Somewhere there is a problem with how these texts are being delivered. It also appears to be just AT&T. None of my Verizon friends experience this problem, so by using reasonable deduction, it would seem to be an AT&T problem. Of course, I've spoken with many a representative of AT&T with no resolution. It may soon be time to switch.