Why do multiple attachments have to send as separate messages?

[Android Central Question]

I have an S7. When I try to send multiple pictures, or a message with a picture, a notification pops up saying the attachments will be sent as separate messages. I don't want it to do that. If I wanted it to do that, I would manually do it myself. How do I override my phone and make it send multiple attachments in one message like I intend?