A rule that replies each time someone writes, not once in 12 hours.
Steps
Open your Freffo group in WhatsApp.
Type, or say it in a voice note: "Jab bhi koi Hi bheje, har baar Hello reply kar dena"
It shows the rule and sets it on your yes. It waits till they stop writing (a few seconds) and answers all of it in one reply, up to 40 answers a day to one person.
Then you can ask
“Jab bhi koi Good morning bheje, har baar Good morning reply karna”