This was in 2014 when WhatsApp started becoming famous for connecting people via groups all over India. My father's college circle - a batch of about 300 in the 1980s, was connecting over WhatsApp. Growing by the day, they had soon reached the maximum limit of 50. My college neighbor and I spent a weekend experimenting with several unofficial WhatsApp APIs. We were able to get 100+ people to communicate with each other seamlessly. I had a spare sim card that we used as a middleman - a phone number added to each of the groups whose sole job was to listen and forward messages from one group to another. We hosted this on AWS. They used this for a couple months until WhatsApp gradually increased the number from 50 to 100 to eventually 250. Digress: WhatsApp should actually look into this; with the current limit set at ~250, imagine if a political group creates 100s of such linked groups and enables mass communication for their political agenda.