The person you're replying to probably meant MMS which can be used for group texting as you're describing.

The fragmented and quirky MMS implementations in the wild render MMS functionally useless, especially compared to what feature set an app can have. I've seen MMS implementations that send replies to only the sender of the original (so some replies, from better implementations, end up in the MMS group, and some end up only sent back to the sender, resulting in confusion); I've seen MMS implementations that allow you to "like" a message, and this is implemented by just sending "I liked this." as a message back to the other clients — which can't interpret it as anything other than just a normal message — resulting in confusion.

Did you know that MMS can transmit slideshows[1]? I didn't, until my father somehow sent me one. The UI that Android has for that is — naturally — a complete afterthought. (No way to pause the slideshow, no way to navigate the slides, nothing. Just one run through the animation at Warp 8.)

[1]: https://en.wikipedia.org/wiki/Multimedia_Messaging_Service

MMS is not a common technology in Europe.

Many European providers are still charging for each MMS. Something like 40cent/MMS.

Ah, I hadn't heard about that before. That's either not available or not common knowledge in the UK.

MMS are available in UK but not popular, because they were heavily overpriced and fundamentally underwhelming when they were introduced 15 years ago. They are also metered like SMS - one of the big wins when switching from SMS to internet-based systems was to stop worrying about yet another limit.