Hey there, and welcome to Apple Support Communities SpiffyCanuck,
We can certainly understand your concern and see you came to us from the article Use Focus on your iPhone or iPad.
We recommend checking out these steps for more information on how to mute a group text.
" How to mute a group text message
- Tap the group text message.
- Tap the group icons at the top of the thread. If you're on iOS 14 or earlier, tap the group icons at the top, then tap the Info button .
- Scroll down, then turn on Hide Alerts.
Or, from your list of messages conversations, you can swipe left over the group text message and tap the Alerts button . With iOS 15, When Hide Alerts is on, the Hide Alerts icon appears next to the conversation on the right side. With iOS 14 or earlier, a crescent moon icon will appear next to the conversation.
Hide Alerts stops notifications for a specific group text message, but not for all the messages on your device. You'll still receive all other messages and notifications. Learn more about managing your notifications."
For additional information, check out this link: Leave a group text message thread on your iPhone or iPad - Apple Support
These steps will help ensure your device is working with ease and can fix common issues like the ones you’re experiencing.
Kindest regards!