Why am I not receiving text messages from some Iphone users in a group text?

[Android Central Question]

Here's my issue and let me just say that it has worked before in the past but I cannot figure out why now I'm having this issue. I have a galaxy s8 and when I create a group text to iPhone and android users, I always receive all replies from the android users in the group message. Not the case with the iPhone users; if they reply I only receive the replies in the group text from some iPhone users. Other iPhone users can be replying all day but I will never get them. Can someone please help?