Hi Monika,
In SEPM, the reports that you get from the reports page are generic representation of the logs. So it will not provide you with the specific information, like computer names. However, it can definitely help you to track down which group is running out of definitions.
You can confugure scheduled reports to automate the process.
You can also confugre notification alerts if machines are out of date. That can be achieved from Monitors->Notifications.
When you add a notification, you can select when do you want to be notified. When 10 machines are out of date, 20 or 30.
Best,
Aniket