A Spreadsheet-bound apps script solution to conduct automated status monitoring on websites listed by the user in a Google Sheets management file. A separate status log file in Google Sheets will be created so that users can easily integrate data with BI services such as Google Data Studio. Notifications of changes in website status will be sent to the user’s Gmail. An optional setting to send notifications to Google Chat is available.

Nice example of using Google Chat for individual/group notification. The developer of this is also very responsive on Github if you encounter issues or have suggested changes.

Source: Website Status Monitoring using Google Sheets