I have a very different opinion about this pump group though it is limited to those that operated on bittrex exchange because they are always few minutes late and by the time the coin name is released the price had doubled and you will be buying into an already over pumped coin.
Is that a particular group or just your experience with various groups?
What you´re describing there is not uncommon, so it´s all about doing your homework to find out who you should put your faith in. I guess the easiest way is to monitor various groups and go to the exchange where the coin is announced to be pumped, and check trade history. Then it´s easy to see in the historical trades if there were unusual volumes bought in the minutes up to the point of the announcement. If that´s the case, simply put a thumb down next to them in your research sheet.