Facebook Group API Feed or Collection

I have a private facebook group that I need to check for new comments using a cronjob or webhook if available. I am not familiar with all the different facebook apis. I need to collect these comments and process them in a special manor. I am looking for someone that can assist me in the collection of the comments. I need a PHP code that can collect all comments since last check. I need these comments stored in an array or object that I can loop through and process. I will create the code that processes the comments once the loop is created. If this is something you can help with please place the word facebook at the top of your reply or your quote will be ignored as I am tired of people not reading my project descriptions.