Name them once: one message for all of them, sent on one send.
Steps
Open your Freffo group in WhatsApp.
Type, or say it in a voice note: "4 log jo site par gaye hain, unhe bolo aaj ka status bhejein"
You see one message with everyone it goes to; on send each gets it, about half a minute apart. 2 to 20 people you already chat with, and what you call them is remembered.
Then you can ask
“Ramesh, Suresh aur Mohan ko bolo kal 9 baje site pe aana”