I have just joined a parents WhatsApp group and have received an unsolicited individual message from one of the others in it who does private violin lessons, asking me if I’d be interested for DD. I think it’s a bit cheeky to be taking phone numbers from the group and using it like this and although I’d like to stay in the group I don’t want just anyone to have my phone number. Is there anything in the WhatsApp settings I can do?