Thank you for your feature request. Error groups are based on the stack trace and not the message. Although there is an option to group by error message, this is not recommended, because it can lead to excessive error groups.
Another recommendation would be to update the version of your hasher for optimal error grouping. You can read more about the different provider hashers and versions here:
At the moment, we're not looking at being able to group errors based on regex due to its unbounded nature:
Thanks again for this feature request.