[logback-user] Question

We have the following use case and would like to know what is the best practice in logback framework. Basically, we are trying to use the SMTP logger appender to send alert email when the erorr is occured.  The issue is that we would like to generate a summary messages (which including, for example, about 100 errors which occured within the given time frame) and send only one email.  The reason for it is to reduce the number of email to avoid flush the email server.  Please let us know what is the best way to configure the logback to satisfy the use case above. Thanks a lot. Louie